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OBJECTIVES There is a lack of guidance on the management of febrile neutropenia in otherwise healthy children, including the need for hospitalization and antibiotic administration, leading to significant practice variation in management. The aim of this initiative was to decrease the number of unnecessary hospitalizations and empirical antibiotics prescribed by 50% over a 24-month period for well-appearing, previously healthy patients older than 6 months presenting to the emergency department with a first episode of febrile neutropenia. METHODS A multidisciplinary team of stakeholders was assembled to develop a multipronged intervention strategy using the Model for Improvement. A guideline for the management of healthy children with febrile neutropenia was created, coupled with education, targeted audit and feedback, and reminders. Statistical control process methods were used to analyze the primary outcome of the percentage of low-risk patients receiving empirical antibiotics and/or hospitalization. Balancing measures included missed serious bacterial infection, emergency department (ED) return visit, and a new hematologic diagnosis. RESULTS Over the 44-month study period, the mean percentage of low-risk patients hospitalized and/or who received antibiotics decreased from 73.3% to 12.9%. Importantly, there were no missed serious bacterial infections, no new hematologic diagnoses after ED discharge, and only 2 ED return visits within 72 hours without adverse outcomes. CONCLUSIONS A guideline for the standardized management of febrile neutropenia in low-risk patients increases value-based care through reduced hospitalizations and antibiotics. Education, targeted audit and feedback, and reminders supported sustainability of these improvements.

Warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome (WS) is a combined immunodeficiency caused by gain-of-function mutations in the C-X-C chemokine receptor type 4 (CXCR4) gene. We characterize a unique international cohort of 66 patients, including 57 (86%) cases previously unreported, with variable clinical phenotypes. Of 17 distinct CXCR4 genetic variants within our cohort, 11 were novel pathogenic variants affecting 15 individuals (23%). All variants affect the same CXCR4 region and impair CXCR4 internalization resulting in hyperactive signaling. The median age of diagnosis in our cohort (5.5 years) indicates WHIM syndrome can commonly present in childhood, although some patients are not diagnosed until adulthood. The prevalence and mean age of recognition and/or onset of clinical manifestations within our cohort were infections 88%/1.6 years, neutropenia 98%/3.8 years, lymphopenia 88%/5.0 years, and warts 40%/12.1 years. However, we report greater prevalence and variety of autoimmune complications of WHIM syndrome (21.2%) than reported previously. Patients with versus without family history of WHIM syndrome were diagnosed earlier (22%, average age 1.3 years versus 78%, average age 5 years, respectively). Patients with a family history of WHIM syndrome also received earlier treatment, experienced less hospitalization, and had less end-organ damage. This observation reinforces previous reports that early treatment for WHIM syndrome improves outcomes. Only one patient died; death was attributed to complications of hematopoietic stem cell transplantation. The variable expressivity of WHIM syndrome in pediatric patients delays their diagnosis and therapy. Early-onset bacterial infections with severe neutropenia and/or lymphopenia should prompt genetic testing for WHIM syndrome, even in the absence of warts.

Classification of inherited bone marrow failure syndromes (IBMFSs) according to clinical and genetic diagnoses enables proper adjustment of treatment. Unfortunately, 30% of patients enrolled in the Canadian Inherited Marrow Failure Registry (CIMFR) with features suggesting hereditability could not be classified with a specific syndromic diagnosis. We analyzed the outcome of hematopoietic stem cell transplantation (HSCT) in unclassified IBMFSs (uIBMFSs) and the factors associated with outcome. Twenty-two patients with uIBMFSs and 70 patients with classified IBMFSs underwent HSCT. Five-year overall survival of uIBMFS patients after HSCT was inferior to that of patients with classified IBMFSs (56% vs 76.5%). The outcome of patients with uIBMFS who received cord blood was significantly lower than that of patients who received other stem cell sources (14.8% vs 90.9%). Engraftment failure was higher among patients with uIBMFS who received cord blood than those who received bone marrow. None of the following factors were significantly associated with poor survival: transfusion load, transplant indication, the intensity of conditioning regimen, human leukocyte antigen-identical sibling/alternative donor. We suggest that identifying the genetic diagnosis is essential to modulate the transplant procedure including conditioning agents and stem cell sources for better outcome and the standard cord blood transplantation (CBT) should be avoided in uIBMFS.

Children with cancer experience suffering, particularly at the end of life. Pediatric hematology/oncology (PHO) fellows need dedicated palliative care (PC) training in order to adequately manage this suffering. Our objectives were to understand (1) the PC training needs of Canadian PHO fellows and (2) experiences in providing PC, from the perspectives of fellows and their training program directors (PDs) and to describe (1) our experience in enhancing our institutional PC curriculum and (2) the preliminary evaluation of this curriculum. Electronic surveys were sent to all Canadian PHO fellows and PDs. Fellows participating in our curriculum were also sent post-course surveys. All 9/9 of the PDs and 63% (29/46) of the fellows completed our pre-course surveys. The majority of survey participants agreed that PHO fellows require dedicated PC training. All programs provided some PC education, but 45% of programs offered 3 or fewer hours of training per year. Only 55% (5/9) of the PDs believed that their trainees had adequate PC skills on completion of training. Fellows perceived a range of PC skills to be important but expressed low levels of comfort across these skills. Many fellows had experienced distress as a result of managing PC clinical situations, and many cited a lack of training as contributing to their distress. Despite increasing awareness of the importance of PC education for PHO fellows, this subject does not receive adequate attention in training curricula. The introduction of a Canadian national curriculum may improve the provision of PC training in education programs.

Primary Subject area Emergency Medicine - Paediatric Background While the management of febrile neutropenia in patients with cancer has clear, evidence-based guidelines, the management of previously healthy, immunocompetent children with a febrile illness and first episode of neutropenia is less understood. These patients are often similarly treated with empiric antibiotics and hospitalization despite studies demonstrating that this population, if they are well-appearing with a short history of neutropenia, is at low risk of serious bacterial infections. Therefore, less aggressive management should be considered in patients meeting low risk criteria. Objectives The aim of our quality improvement (QI) study was to decrease the number of unnecessary hospitalizations and empiric antibiotics prescribed by 50% over a 12-month period for otherwise healthy, well appearing patients presenting to the emergency department (ED) with a first episode of febrile neutropenia. Design/Methods A team of stakeholders from Hematology, Infectious Disease, Pediatrics and Emergency Medicine was assembled. A review of the literature, peer institutions and local practices of managing febrile neutropenia in healthy children was performed. Using the Model for Improvement, a guideline for the management of healthy children with first episode of febrile neutropenia was developed and refined using PDSA cycles. In January 2020, the guideline was launched for clinical use in the ED. Education, targeted audit and feedback, pathway modifications, and reminders were used to address knowledge gaps and staff turnover. A family of measures was analyzed using run charts and statistical process control (SPC) methods. Results Eighteen months of baseline data identified nineteen low risk patients with 84% either hospitalized and/or received antibiotics. It was also uncovered that many patients were misdiagnosed with neutropenia by excluding bands from the absolute neutrophil count (ANC). After the first twelve months of the intervention, sixteen patients met low risk criteria. Hospitalization and/or antibiotics use for this population decreased to 25% and all blood cultures were negative. Recognition of true severe febrile neutropenia also improved. Forty-one patients had a neutrophil count < 0.5, but an ANC > 0.5. Hospitalization and/or antibiotics use for this population decreased from 52% to 10%. Conclusion Through a multi-faceted, multidisciplinary QI study, we improved resource stewardship and value-based care by reducing unnecessary hospitalizations and antibiotics in low risk patients with a first episode of febrile neutropenia. Next steps include iterations to the guideline to increase impact along with sustainability planning. This work can easily be adopted by other pediatric and community sites caring for children.

To assess the cost-effectiveness of an evidence-informed institutional protocol for physicians that encouraged management of children with newly diagnosed immune thrombocytopenia with observation over active therapy, where appropriate.We conducted a probabilistic cost-effectiveness analysis from an institutional perspective using a decision tree with a one year time horizon. Patient-level data was retrospectively ascertained for children diagnosed in pre-protocol (2007-2009) and post-protocol (2013-2018) time periods. ITP resolution was defined as achieving a sustained platelet count of100×10Forty-eight patients were followed for one year in the pre-protocol period and 84 in the post-protocol period. After protocol implementation, an average cost savings per child managed of $2055 (95% CI: $656, $3890) CAD was observed, as was a higher proportion of resolved ITP cases. The implementation strategy remained less costly and more effective in 99.7% of model iterations.Implementation of an evidence-informed institutional protocol to guide physicians towards increased uptake of observation over active therapy when managing children with newly diagnosed ITP resulted in significant cost savings on a per case basis, even after accounting for training-related costs. Though the long-term cost implications regarding the sustainability of the intervention are not yet known, it is anticipated that continued institutional savings could occur.

The distinction between myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) often relies on an arbitrary marrow blast cutoff of 30% in pediatrics and 20% in adults. There is little data about the treatment of children with extramedullary myeloid malignancy that has features of both, MDS and AML. Herein, we report for the first time 2 patients MDS/AML (1 with Shwachman-Diamond syndrome and 1 with idiopathic MDS and monosomy 7) who presented with extramedullary complications, received treatment with azacitidine, achieved complete remission and subsequently underwent hematopoietic stem cell transplantation.

Progressive cytopenia is a serious complication among paediatric patients with inherited bone marrow failure syndromes (IBMFS). Androgens have been used to improve blood counts in different bone marrow failure conditions. Little is known about efficacy and toxicity with new androgens (i.e., danazol) in different types of IBMFS. We identified 29 patients from the Canadian Inherited Marrow Failure Registry, who received oxymetholone or danazol. Sixteen (55%) had haematological response including patients with unclassified IBMFS (45%). Danazol showed a better toxicity profile and similar efficacy compared to oxymetholone. Androgens are an effective and safe option to ameliorate bone marrow failure in IBMFS.

BACKGROUND: Total splenectomy (TS) and partial splenectomy (PS) are used for children with congenital hemolytic anemia (CHA), although the long-term outcomes of these procedures are poorly defined. This report describes long-term outcomes of children with CHA requiring TS or PS. PROCEDURE: We collected data from children ages 2-17 with hereditary spherocytosis (HS) or sickle cell disease (SCD) requiring TS or PS from 1996 to 2016 from 14 sites in the Splenectomy in Congenital Hemolytic Anemia (SICHA) consortium using a prospective, observational patient registry. We summarized hematologic outcomes, clinical outcomes, and adverse events to 5 years after surgery. Hematologic outcomes were compared using mixed effects modeling. RESULTS: Over the study period, 110 children with HS and 97 children with SCD underwent TS or PS. From preoperatively compared to postoperatively, children with HS increased their mean hemoglobin level by 3.4 g/dL, decreased their mean reticulocyte percentage by 6.7%, and decreased their mean bilirubin by 2.4mg/dL. Hematologic improvements and improved clinical outcomes were sustained over 5 years of follow-up. For children with SCD, there was no change in hemoglobin after PS or TS following surgery, although all clinical outcomes were improved. Over 5 years, there was one child with HS and 5 children with SCD who developed post-splenectomy sepsis. CONCLUSIONS: For children with HS, there are excellent long-term hematologic and clinical outcomes following either PS or TS. Although hemoglobin levels do not change after TS or PS in SCD, the long-term clinical outcomes for children with SCD are favorable.

Background Myelodysplastic syndromes (MDS) represent a group of clonal hematopoietic stem cell disorders that commonly progress to acute myeloid leukemia (AML). The diagnostics, prognostics, and treatment of adult MDS are established but do not directly translate to children and adolescents. Pediatric MDS is a rare disease, characterized by unique cytogenetics and histology compared with adult MDS, and often arises secondary to germline predisposition or cytotoxic exposures. Our objective was to highlight aspects of diagnosis/management that would benefit from further systematic review toward the development of clinical practice guidelines for pediatric MDS. Procedure The North American Pediatric Aplastic Anemia Consortium (NAPAAC) is composed of collaborative institutions with a strong interest in pediatric bone marrow failure syndromes and hematologic malignancies. The NAPAAC MDS working group developed a national survey distributed to 35 NAPAAC institutions to assess data on (1) clinical presentation of pediatric MDS, (2) diagnostic evaluation, (3) criteria for diagnosis, (4) supportive care and treatment decisions, and (5) role of hematopoietic stem cell transplantation (HSCT). Results Twenty-eight of 35 institutions returned the survey. Most centers agreed on a common diagnostic workup, though there was considerable variation regarding the criteria for diagnosis. Although there was consensus on supportive care, treatment strategies, including the role of cytoreduction and HSCT, varied across centers surveyed. Conclusions There is lack of national consensus on diagnosis and treatment of pediatric MDS. This survey identified key aspects of MDS management that will warrant systematic review toward the goal of developing national clinical practice guidelines for pediatric MDS.

Background ERCC6L2‐associated disorder has recently been described and only five patients were reported so far. The described phenotype included bone marrow, cerebral, and craniofacial abnormalities. The aim of this study was to further define the genetic and phenotypic spectrum of the disorder by summarizing the five published cases and an additional case that we identified through whole‐exome sequencing performed at the University of Toronto. Methods Clinical data was extracted from the Canadian Inherited Marrow Failure Registry. Whole exome sequencing was performed to identify causative mutations. Results All six cases had homozygous truncating mutations either at or upstream of the helicase domain of ERCC6L2. All patients displayed bone marrow failure, learning or developmental delay and microcephaly. Our patient was unique in displaying features of cerebellar disease, including ataxia and dysmetria as well as an interval deterioration of the corpus callosum and generalized volume loss on MRI. Another unique feature of our patient was retinal dystrophy with macular involvement. Along with one other patient, our patient displayed craniofacial abnormalities by presenting with low‐set prominent ears, a pointed prominent chin, and deep‐set eyes. Leukemia is common among patients with inherited bone marrow failure, but thus far, none of the patients have developed this complication. Conclusions ERCC6L2‐associated disorder is a multisystem disorder. The phenotype spectrum includes bone marrow failure, cerebral, and craniofacial abnormalities, as well as cerebellar and retinal abnormalities.

Introduction: Dyskeratosis congenita (DC) is an inherited bone marrow failure syndrome caused by mutations in one of 13 telomere-related genes, resulting in disruption of normal telomere maintenance; however, about 30% of patients do not have a molecular diagnosis. DC patients are at increased risk for severe bone marrow failure (SBMF), myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), and solid tumours. Life expectancy is compromised by SBMF, malignancy, pulmonary and liver fibrosis, and GI bleeding. Objectives: Among patients with DC in Canada, aims were to: (1) characterize the genetic profile of DC in Canada, (2) define the spectrum of clinical features of DC, (3) determine the incidence and age when SBMF, MDS, AML or solid tumours develop, (4) identify factors that are associated with higher mortality risk, and (5) describe the causes of death. Methods: Data of patients enrolled in the Canadian Inherited Marrow Failure Registry (CIMFR) and meeting diagnostic criteria for DC between January 1, 2001 and March 1, 2018 were included. The CIMFR is a multicentre registry that captures data on patients with inherited marrow failure syndromes from pediatric tertiary referral centres across all Canadian provinces. We investigated several continuous (e.g. age at diagnosis of SBMF/MDS/AML) and categorical (e.g. mutated gene) variables that are associated with specific outcomes, namely overall survival and development of SBMF. Cox proportional hazard models were used to assess risk of death based on age at diagnosis and presence of SBMF. Kaplan-Meier curves were used to assess overall survival. Results: As of March 1st, 2018, 35 patients with DC were enrolled. The mean age of diagnosis was 10.94 years (0-39.9). The underlying genotypes were: DKC1 (7), TERT (6), TINF2 (5), RTEL1 (3), PARN (2), TERC (2) but remained undetermined in the others (10). Twenty-seven patients were classified as classical DC, 7 had Hoyeraal-Hreidarsson syndrome and 1 patient had Coats plus syndrome. Eight patients (23%) developed SBMF. The mean age of SBMF was 4.22 years (1-8.66). No statistical difference was found between genotypes and progression to SBMF (P=0.1). Modelling death as a function of time varying SBMF status using a cox proportional hazard regression model showed that the presence of SBMF in DC patients was predictive of higher mortality rate (P= 0.009, hazard ratio 5.7, CI 1.54-21.5). None of the patients developed malignancy during childhood (0-18 years). One adult patient developed skin cancer. Eleven patients (31%) received a hematopoietic stem cell transplant (HSCT). The mean age of HSCT was 9.5 years (0.5-37). Ten (29%) patients died, five of whom were recipients of HSCT. Mean age of death was 12.98 years (2-24.6). Extra-hematological complications included gastrointestinal bleeding (50%), pulmonary fibrosis (40%), overwhelming infection (40%), liver fibrosis (20%), cardiomyopathy (10%), hemolytic uremic syndrome (HUS) (10%) and thrombotic microangiopathy (TMA) (10%). Most patients had more than one organ dysfunction. Analysis of survival showed that all patients with TINF2 mutations have died (at median age of 10.8 years, range 2.5-23.25) whereas none died in the TERT group. Patients diagnosed at younger age had lower overall survival compared to patients diagnosed at older ages (P= 0.03, HR: 0.72, CI: 0.57-0.90). All deaths were due to organ dysfunction related to DC. Fifty percent of the patients had concurrent SBMF at the time of death. Conclusion: In this analysis, we characterised the genetic and phenotypic spectrum of DC patients registered in the CIMFR. We found a high mortality rate mainly related to organ dysfunction and SBMF, and described the impact of genotype, earlier age at diagnosis and presence of SBMF in predicting survival. We found that malignancy is an uncommon complication in the pediatric age group. Figure Disclosures Klaassen: Amgen Inc: Consultancy; TranQoL and KIT: Other: creater and owner of Kids ITP tool and TranQoL; Octapharma AG: Speakers Bureau; Baxalta: Speakers Bureau; Biogen Canada Limited: Speakers Bureau; Novo Nordisk Canada Inc: Consultancy; Hoffman-LaRoche Ltd: Consultancy; Agios Pharmaceuticals Inc: Consultancy; Shire Pharma Canada Inc: Consultancy. Pastore:Pfizer: Honoraria. Lipton:BMS: Consultancy, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria; Novartis: Consultancy, Research Funding; Ariad: Consultancy, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding.

Inherited bone marrow failure syndromes (IBMFSs) are genetically heterogeneous disorders with cytopenia. Many IBMFSs also feature physical malformations and an increased risk of cancer. Point mutations can be identified in about half of patients. Copy number variation (CNVs) have been reported; however, the frequency and spectrum of CNVs are unknown. Unfortunately, current genome-wide methods have major limitations since they may miss small CNVs or may have low sensitivity due to low read depths. Herein, we aimed to determine whether reanalysis of NGS panel data by normalized coverage value could identify CNVs and characterize them. To address this aim, DNA from IBMFS patients was analyzed by a NGS panel assay of known IBMFS genes. After analysis for point mutations, heterozygous and homozygous CNVs were searched by normalized read coverage ratios and specific thresholds. Of the 258 tested patients, 91 were found to have pathogenic point variants. NGS sample data from 165 patients without pathogenic point mutations were re-analyzed for CNVs; 10 patients were found to have deletions. Diamond Blackfan anemia genes most commonly exhibited heterozygous deletions, and included RPS19, RPL11, and RPL5. A diagnosis of GATA2-related disorder was made in a patient with myelodysplastic syndrome who was found to have a heterozygous GATA2 deletion. Importantly, homozygous FANCA deletion were detected in a patient who could not be previously assigned a specific syndromic diagnosis. Lastly, we identified compound heterozygousity for deletions and pathogenic point variants in RBM8A and PARN genes. All deletions were validated by orthogonal methods. We conclude that careful analysis of normalized coverage values can detect CNVs in NGS panels and should be considered as a standard practice prior to do further investigations.

Primary immunodeficiency disorders represent a heterogeneous spectrum of diseases, predisposing to recurrent infections, allergy, and autoimmunity. While an association between primary immunodeficiency disorders and increased risk of cancer has been suggested since the 1970s, renewed attention has been given to this topic in the last decade, largely in light of the availability of large registries as well as advances in next generation sequencing. In this narrative review, we will give an insight of the primary immunodeficiencies that are commonly responsible for the greater number of cancers in the primary immunodeficiency disorders population. We will describe clinical presentations, underlying genetic lesions (if known), molecular mechanisms for carcinogenesis, as well as some management considerations. We will also comment on the future directions and challenges related to this topic.Conclusion: The awareness of the association between several primary immunodeficiencies and cancer is crucial to provide the best care for these patients.What is Known: • Patients with primary immunodeficiency have an increased risk of malignancy. The type of malignancy is highly dependent on the specific primary immunodeficiency disorder.What is New: • Survival in patients with primary immunodeficiency disorders has been improving, and conversely also their lifetime risk of malignancy. • International collaboration and multinational registries are needed to improve our knowledge and therapeutic strategies.

Venous thromboembolism (VTE) is now increasingly recognized within paediatrics. A Canadian VTE registry has estimated the incidence as 0.7 to 1.0 per 100,000 population, with a peak in infancy and adolescence. Congenital inferior vena cava agenesis (IVCA) is an important risk factor that may be unfamiliar to paediatricians. Several case reports have since described an association between IVCA, VTE, and renal hypoplasia, which has been referred to as KILT syndrome (Kidney and IVC abnormalities with Leg Thromboses). We describe the first reported paediatric case of KILT syndrome in Canada. In any young patient presenting with a spontaneous DVT, particularly, if it is bilateral in nature with no co-existing risk factors for thrombus formation, we recommend investigating for the possibility of an underlying congenital vena cava anomaly. The use of prolonged anticoagulant therapy is supported by the inherent life-long risk of recurrent thrombosis associated with IVC anomalies.

Kaposiform hemangioendothelioma (KHE) is a rare infiltrative vascular tumor that may be associated with Kasabach-Merritt Phenomenon (KMP), which is a consumptive coagulopathy with potentially life-threatening thrombocytopenia. Management of KHE and KMP is challenging, and currently, there are no standardized validated treatment protocols. Mammalian target of rapamycin inhibitors have been shown to be effective in the treatment of KHE. We describe a term male who presented as a diagnostic dilemma with life-threatening pleural and pericardial effusions and severe thrombocytopenia. After extensive work-up the etiology for his condition was determined to be KHE with KMP. The patient was commenced on sirolimus and responded well to therapy with resolution of KMP.

IVIG has been the predominant therapy for the initial management of children with newly diagnosed immune thrombocytopenia at our hospital. With current guidelines supporting more conservative management, we undertook a quality improvement initiative to lead practice change. Over a 2-year time period (2013 to 2015), we strove to decrease use of hospital resources (use of IVIG, length of stay) while optimizing family satisfaction. An interdisciplinary working group was struck and a quality improvement bundle was implemented. The bundle comprised a patient information sheet; an evidence-informed, consensus-based protocol; and promotion of shared decision-making via stakeholder engagement and education. Data were collected prospectively; baseline data from a 2007 to 2009 audit were used for comparison. In total, 27 patients were included. Mean initial platelet count was 4×10/L. Bleeding was classified as none or mild in 56% of patients. IVIG use decreased from 88% to 55% of patients, corticosteroid prescription increased from 6% to 15%, and observation increased from 6% to 30% of patients. Hospital length of stay decreased from 47 to 36 hours. Family satisfaction was stable across treatment groups. Through introduction of a quality improvement initiative, we were able to improve family-centered care and decrease use of hospital resources.

The purpose of this study was to define the hematologic response to total splenectomy (TS) or partial splenectomy (PS) in children with hereditary spherocytosis (HS) or sickle cell disease (SCD).The Splenectomy in Congenital Hemolytic Anemia (SICHA) consortium registry collected hematologic outcomes of children with CHA undergoing TS or PS to 1 year after surgery. Using random effects mixed modeling, we evaluated the association of operative type with change in hemoglobin, reticulocyte counts, and bilirubin. We also compared laparoscopic to open splenectomy.The analysis included 130 children, with 62.3% (n=81) undergoing TS. For children with HS, all hematologic measures improved after TS, including a 4.1g/dl increase in hemoglobin. Hematologic parameters also improved after PS, although the response was less robust (hemoglobin increase 2.4 g/dl, p0.001). For children with SCD, there was no change in hemoglobin. Laparoscopy was not associated with differences in hematologic outcomes compared to open. TS and laparoscopy were associated with shorter length of stay.Children with HS have an excellent hematologic response after TS or PS, although the hematologic response is more robust following TS. Children with SCD have smaller changes in their hematologic parameters. These data offer guidance to families and clinicians considering TS or PS.

Background Phenotypic overlap among the inherited bone marrow failure syndromes (IBMFSs) frequently limits the ability to establish a diagnosis based solely on clinical features. >70 IBMFS genes have been identified, which often renders genetic testing prolonged and costly. Since correct diagnosis, treatment and cancer surveillance often depend on identifying the mutated gene, strategies that enable timely genotyping are essential. Methods To overcome these challenges, we developed a next-generation sequencing assay to analyse a panel of 72 known IBMFS genes. Cases fulfilling the clinical diagnostic criteria of an IBMFS but without identified causal genotypes were included. Results The assay was validated by detecting 52 variants previously found by Sanger sequencing. A total of 158 patients with unknown mutations were studied. Of 75 patients with known IBMFS categories (eg, Fanconi anaemia), 59% had causal mutations. Among 83 patients with unclassified IBMFSs, we found causal mutations and established the diagnosis in 18% of the patients. The assay detected mutant genes that had not previously been reported to be associated with the patient phenotypes. In other cases, the assay led to amendments of diagnoses. In 20% of genotype cases, the results indicated a cancer surveillance programme. Conclusions The novel assay is efficient, accurate and has a major impact on patient care.

Diamond-Blackfan anemia (DBA) features hypoplastic anemia and congenital malformations, largely caused by mutations in various ribosomal proteins. The aim of this study was to characterize the spectrum of genetic lesions causing DBA and identify genotypes that correlate with phenotypes of clinical significance. Seventy-four patients with DBA from across Canada were included. Nucleotide-level mutations or large deletions were identified in 10 ribosomal genes in 45 cases. The RPS19 mutation group was associated with higher requirement for chronic treatment for anemia than other DBA groups. Patients with RPS19 mutations, however, were more likely to maintain long-term corticosteroid response without requirement for further chronic transfusions. Conversely, patients with RPL11 mutations were less likely to need chronic treatment. Birth defects, including cardiac, skeletal, hand, cleft lip or palate and genitourinary malformations, also varied among the various genetic groups. Patients with RPS19 mutations had the fewest number of defects, while patients with RPL5 had the greatest number of birth defects. This is the first study to show differences between DBA genetic groups with regards to treatment. Previously unreported differences in the rate and types of birth defects were also identified. These data allow better patient counseling, a more personalized monitoring plan, and may also suggest differential functions of DBA genes on ribosome and extra-ribosomal functions.

Inherited bone marrow failure syndromes comprise a genetically heterogeneous group of diseases with hematopoietic failure and a wide array of physical malformations. Copy number variants were reported in some inherited bone marrow failure syndromes. It is unclear what impact copy number variants play in patients evaluated for a suspected diagnosis of inherited bone marrow failure syndromes. Clinical and genetic data of 323 patients from the Canadian Inherited Marrow Failure Registry from 2001 to 2014, who had a documented genetic work-up, were analyzed. Cases with pathogenic copy number variants (at least 1 kilobasepairs) were compared to cases with other mutations. Genotype-phenotype correlations were performed to assess the impact of copy number variants. Pathogenic nucleotide-level mutations were found in 157 of 303 tested patients (51.8%). Genome-wide copy number variant analysis by single-nucleotide polymorphism arrays or comparative genomic hybridization arrays revealed pathogenic copy number variants in 11 of 67 patients tested (16.4%). In four of these patients, identification of copy number variant was crucial for establishing the correct diagnosis as their clinical presentation was ambiguous. Eight additional patients were identified to harbor pathogenic copy number variants by other methods. Of the 19 patients with pathogenic copy number variants, four had compound-heterozygosity of a copy number variant with a nucleotide-level mutation. Pathogenic copy number variants were associated with more extensive non-hematological organ system involvement (p = 0.0006), developmental delay (p = 0.006) and short stature (p = 0.04) compared to nucleotide-level mutations. In conclusion, a significant proportion of patients with inherited bone marrow failure syndromes harbor pathogenic copy number variants which were associated with a more extensive non-hematological phenotype in this cohort. Patients with a phenotype suggestive of inherited bone marrow failure syndromes but without identification of pathogenic nucleotide-level mutations should undergo specific testing for copy number variants., Blood disorders: impact of genomic structural variation Copy number variation in patients with inherited bone marrow failure syndromes (IBMFSs) is associated with more severe clinical symptoms. In addition to persistently low levels of red blood cells, white blood cells and/ or platelets, patients with IBMFSs also present varying degrees of physical malformations. Most cases are associated with single base-pair mutations in the DNA sequence, but Canadian researchers led by Yigal Dror at The Hospital for Sick Children in Toronto, have found that whole sections of the genome are deleted or repeated in an important proportion of patients. Those carrying copy number variants (CNV) presented more commonly with developmental delay, short stature and defects in more organ systems, than patients with point mutations. CNV analysis of patients with suspected IBMFSs could aid early disease evaluation and management.

The outcomes of children with congenital hemolytic anemia (CHA) undergoing total splenectomy (TS) or partial splenectomy (PS) remain unclear. In this study, we collected data from 100 children with CHA who underwent TS or PS from 2005–2013 at 16 sites in the Splenectomy in Congenital Hemolytic Anemia (SICHA) consortium using a patient registry. We analyzed demographics and baseline clinical status, operative details, and outcomes at 4, 24, and 52 weeks after surgery. Results were summarized as hematologic outcomes, short-term adverse events (AEs) (≤ 30 days after surgery), and long-term AEs (31–365 days after surgery). For children with hereditary spherocytosis, after surgery there was an increase in hemoglobin (baseline 10.1 ± 1.8 gm/dl, 52 week 12.8 ± 1.6 gm/dl; mean ± SD), decrease in reticulocyte and bilirubin as well as control of symptoms. Children with sickle cell disease had control of clinical symptoms after surgery, but had no change in hematologic parameters. There was an 11% rate of short-term AEs and 11% rate of long-term AEs. As we accumulate more subjects and longer follow-up, use of a patient registry should enhance our capacity for clinical trials and engage all stakeholders in the decision-making process.

Introduction Inherited bone marrow failure syndromes (IBMFSs) are rare genetic disorders characterized by abnormal hematopoiesis resulting in cytopenias and increased risk of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Once patients develop MDS the only curative therapy is hematopoietic stem cell transplant (HSCT). The rate of progression from early MDS to advanced MDS and AML is variable and risk factors for progression in IBMFS patients are poorly defined. We hypothesized that certain variables could predict the likelihood of progression from early stages of IBMFS-associated MDS/clonal hematopoiesis to advanced MDS or AML, and that the type of disease progression may impact overall survival (OS). Methods Data were collected from patients prospectively enrolled in the Canadian Inherited Marrow Failure Registry (CIMFR), a collaboration of 1 adult and 16 pediatric hospitals in Canada that care for >95% of pediatric IBMFS patients. IBMFS patients were diagnosed as having a specific syndrome or unclassified IBMFS (UCIBMFS) based on published criteria from our lab and others'. Diagnostic criteria for pediatric MDS defined by Hasle et al. were used. Progression of MDS was defined as 1 or more of: (1) a new cytogenetic abnormality, (2) progression in cytopathology from refractory cytopenia (RC) or refractory cytopenia with ringed sideroblasts (RCRS) to refractory cytopenia with dysplasia (RCD), refractory cytopenia with excess blasts (RCEB) or AML, or (3) increased degree of cytopenia severity. Time to progression was described by Kaplan-Meier analysis and risk factors were evaluated using the Cox proportional hazards model. Results Of 601 patients enrolled in CIMFR, 59 (9.8%) developed cytogenetic clones/MDS. Thirteen (22%) had Fanconi Anemia (FA), 13 (22%) had Shwachman-Diamond Syndrome (SDS), 10 (16.9%) had UCIBMFS, and 23 (39%) had other marrow failure syndromes (i.e. Dyskeratosis Congenita, Severe Congenital Neutropenia, Diamond Blackfan Anemia, GATA2-related disorders). The majority presented with cytogenetic clones/RC (n=45, 76%), 9 (15%) had RCEB, 3 (5%) RCD and 1 (1.7%) RCRS. The most common cytogenetic abnormalities at presentation were -7/-7q (n=18, 30%) and isochromosome 7q10 (n=7, 12%). Four patients had complex cytogenetics (6.8%). Of the patients who developed MDS, 32 (54%) went to HSCT. Patients who developed MDS had significantly worse OS (HR 3, 95% CI 2 to 6, p Twenty four MDS patients (40%) had disease progression, with a median time to progression of 4.7 months (1.14-131). Nine patients (38%) with disease progression had FA, 5 (21%) had SDS, 4 (17%) had UC, and 6 (25%) had other marrow failure syndromes. Ten patients (42%) developed more advanced cytopathology, 10 (42%) a new cytogenetic abnormality, and 5 (20%) worsening cytopenias. Eight patients progressed from RC to RCEB, with a median time to progression of 5.7 months (1.14 to 113). Progression to more advanced cytopathology was associated with lower OS (HR 2.7, 95% CI 1.0 to 7.4, p=0.046). Median time to progression of cytogenetics was 4.13 months (1.14 to 131), which was not predictive of worse OS (p=0.22). Notably, there was no difference in OS or risk of progression between the -7/-7q and isochromosome 7q groups (p=0.644). Finally, patients who progressed due to worsening cytopenias had significantly lower OS compared to those who did not (p=0.011), but numbers were small. Seventeen (71%) of the MDS patients who progressed underwent HSCT. Conclusion Development of MDS has a significant adverse impact on the OS of IBMFS patients, with disease progression occurring 4.7 months from MDS diagnosis. Progression to advanced cytopathology is associated with decreased survival, while worsening cytogenetic clones and cytopenias may not carry the same risk. Importantly, isochromosome 7q10 is also associated with a risk of progression to more severe hematological disease, and may have an impact on survival. Further analysis of additional variables (i.e. HSCT) will provide insight into the important predictors of survival and disease progression, and help to guide treatment decisions for this high-risk patient population. Disclosures No relevant conflicts of interest to declare.

Background: Over the last decade major progress has been made in developing new diagnostic methods and in phenotypic and molecular classification of inherited bone marrow failure syndromes (IBMFSs). Nevertheless, data from the Canadian Inherited Marrow Failure Registry (CIMFR) indicates that 28% of patients with inherited bone marrow failure syndromes (IBMFS) cannot be assigned a specific syndromic diagnosis. These unclassified IBMFS (UIBMFS) cases may represent either novel syndromes or atypical presentations of previously described disorders. Hematopoietic stem cell transplantation (HSCT) is the only curative option for bone marrow failure and malignant myeloid transformation in IBMFSs. However, it is unknown whether the application of this treatment to UIBMFS patients without an ability to modify the procedure according to the underlying genetic and syndromic diagnosis affects outcome. To our knowledge, there are no published transplant data on cohorts of patients with UIBMFSs. The aims of this study were to evaluate the outcome and prognostic factors of HSCT in a cohort of patients with UIBMFSs and to determine whether the knowledge of the syndromic/genetic diagnosis before HSCT has an impact on transplant outcome. Methods: Patients were enrolled on the CIMFR if they were diagnosed with a specific IBMFSs (e.g. Fanconi anemia), and/or they had bone marrow failure and either a family history of bone marrow, or physical malformations or a diagnosis before the age of one year. Patients were considered as having an UIBMFS if they fulfilled the above criteria, but could not be assigned a specific syndromic diagnosis since they did not meet the diagnostic criteria for any known IBMFS. HSCT data were extracted from the CIMFR database and analyzed. Descriptive statistics were used to compare between groups. Cox proportional hazards model was used for univariate analysis to identify risk factors for worse overall survival post HSCT in patients with UIBMFSs. Results: Among the patients enrolled in the CIMFR, 22 with UIBMFSs and 68 with classified IBMFSs (CIBMFSs) underwent HSCT between January 2001 and December 31, 2017. Transplanted patients with UIBMFSs were hematologically characterized by multilineage cytopenia (n=13), single-lineage cytopenia (n=1), myelodysplastic syndrome (MDS) (n=5) or acute myeloid leukemia (AML) (n=3). Patients with CIBMFSs had Fanconi anemia (n=30), dyskeratosis congenita (n=7), Shwachman-Diamond syndrome (n=9), Kostmann syndrome (n=6), Diamond-Blackfan anemia (n=4) or others (n= 11). Median age at diagnosis of patients with UIBMFSs was 4.18 years (range; 0 to 32.0 years) and median age at HSCT for UIBMFSs was 5.74 years (range; 0.17-66.67 years). Median time between diagnosis of UIBMFS and HSCT was 0.48 years (range; 0.12 - 34.67), this was significantly shorter than that of CIBMFS (1.77 years, range; 0.17 - 15 years, P=0.014). Six patients (27.3%) of UIBMFS and 9 patients (19.7%) with CIBMFS underwent HSCT for MDS-RCEB or AML (P=0.15). The overall 5-year survival of UIBMFS patients was significantly inferior to that of CIBMFS patients: 56±11.4% vs. 76±5.5%, respectively (P=0.047). 5-year overall survival of patients with UIBMFSs was significantly worse among those whose stem cell source was cord blood (15±13.3%) vs. those who received other stem cell sources (91±8.7%, P=0.04), while stem cell source did not affect prognosis of patients with CIBMFSs. Engraftment failure among UIBMFS patients who received cord blood was significantly higher than engraftment failure among those who received bone marrow (55.6% vs. 9.1%, P=0.024). No other factors reached statistical significance when the impact of stem cell source on overall survival was analyzed, including transfusion load, transplant indications, intensity of conditioning regimens, related/non-related donor, degree of human leukocyte antigen (HLA) matching or identifying a diagnosis after HSCT. Conclusion: Identifying the syndromic diagnosis of IBMFSs is critically important when considering HSCT. The worse HSCT outcome of UIBMFSs in this study might be related to an inability to tailor the transplant approach to the patient specific phenotype and genotype. Our data suggest that cord blood should be avoided as a stem cell source in patients with UIBMFSs. Disclosures No relevant conflicts of interest to declare.

There is an Inside Blood Commentary on this article in this issue.

BACKGROUND Technetium-99m-diethylene-triamine-pentaacetate (Tc-99m-DTPA) nuclear medicine studies allow for accurate monitoring of glomerular filtration rate (GFR) in cancer patients receiving chemotherapy. However, these scans may be logistically challenging and are associated with some radiation exposure. OBJECTIVES The purpose of this study was to retrospectively review the use of Tc-99m-DTPA studies to evaluate the subgroup of children with low GFR by Tc-99m-DTPA who may most benefit from this procedure-namely, the patients with a normal serum creatinine (SCr) and GFR estimated by Schwartz (Sch) calculation who may otherwise not have their renal dysfunction recognized. We further determined how the GFR result modified the treatment plan for these patients. METHODS Patients aged 2 to 18 years with solid tumors diagnosed from 2000 to 2007 were identified. Tc-99m-DTPA results, corresponding height and SCr, were recorded and GFR Sch calculated. The clinical course of patients with Tc-99m-DTPA

Inherited bone marrow failure syndromes are a group of rare, heterogeneous genetic disorders with a risk of clonal and malignant myeloid transformation including clonal marrow cytogenetic abnormalities, myelodysplastic syndrome and acute myeloid leukemia. The clinical characteristics, risk classification, prognostic factors and outcome of clonal and malignant myeloid transformation associated with inherited bone marrow failure syndromes are largely unknown. The aims of this study were to determine the impact of category, cytopathology and cytogenetics, the three components of the “Category Cytology Cytogenetics” classification of pediatric myelodysplastic syndrome, on the outcome of clonal and malignant myeloid transformation associated with inherited bone marrow failure. We used data from the Canadian Inherited Marrow Failure Registry. Among 327 patients with inherited bone marrow failure syndrome enrolled in the registry, the estimated risk of clonal and malignant myeloid transformation by the age of 18 years was 37%. The risk of clonal and malignant myeloid transformation varied according to the type of inherited bone marrow failure syndrome but was highest in Fanconi anemia. The development of clonal and malignant myeloid transformation significantly affected overall survival. Mortality varied based on cytopathological group. The largest group of patients had refractory cytopenia. Clonal marrow cytogenetic abnormalities were identified in 87% of patients with clonal and malignant myeloid transformation, and different cytogenetic groups had different impacts on disease progression. We conclude that category, cytopathology and cytogenetics in cases of clonal and malignant myeloid transformation associated with inherited bone marrow failure syndromes have an important impact on outcome and that the classification of such cases should incorporate these factors.

C-KIT encodes a tyrosine kinase receptor (KIT) that, when activated by its ligand (KL), stimulates proliferation, differentiation, migration, and survival. Greater than 70% of epithelial ovarian cancers coexpress c-KIT and KL. C-KIT and KL expression levels have been shown to be up-regulated by cAMP in some cell types. Additionally, cAMP is well-recognized for its anti-proliferative effects in cancer cells. The goal of these experiments was to investigate these seemingly contradictory consequences of cAMP treatment by: (1) confirming the growth inhibitory actions of cAMP on ovarian cancer cells; (2) investigating the ability of cAMP to affect c-KIT and KL expression in these cells; and (3) examining the possible role of endogenous and/or cAMP-regulated c-KIT and KL expression in ovarian cancer cell proliferation. HEY cells, an ovarian cancer cell line which expresses c-KIT and KL, were treated with dibutyryl cyclic AMP (dbcAMP), 8-bromo-cAMP, and cholera toxin over a range of concentrations. With all treatments, stimulation of cAMP signaling caused a dose-dependent inhibition of HEY cell proliferation by up to 40, 62, and 38%, respectively. This inhibition of proliferation correlated with a dose-dependent increase in c-KIT mRNA expression, yielding 4- to 7-fold elevations in transcript abundance; there were no changes in steady-state levels of KL transcripts. In order to determine whether KIT expression/activity was responsible for the observed decrease in proliferation, dbcAMP-treated HEY cells were exposed either to anti-KIT neutralizing antibodies or to the KIT inhibitor STI571. These experiments demonstrated that KIT inhibition did not alter the growth rate of cells or reverse the dbcAMP-induced inhibition of proliferation. These results suggest that cAMP signaling pathways regulate both cell proliferation and c-KIT expression in ovarian cancer cells; however, KIT is not assuming its well-established role as a growth factor.

Myelodysplastic Syndrome (MDS) is a problem of ineffective hematopoesis, due to a clonal disorder of the hematopoetic stem cells. MDS is rare in children and considered premalignant as it often progresses to leukemia over time. There are known inherited predisposing conditions to MDS that have been reported in the literature. We describe the case of a 12-year-old girl with multiple dysmorphic features, short stature, and developmental delay with a new diagnosis of MDS (RAEB) with no confirmed genetic diagnosis linking all these features together. We propose that her underlying syndromic diagnosis may have predisposed her to MDS.

Background. Inherited bone marrow failure syndromes (IBMFSs) comprise a genetically heterogeneous group of diseases with hematopoietic failure and varying degrees of physical malformations. The diagnosis of an IBMFS and categorizing the specific syndrome critically impact on clinical care; however, these are commonly challenging and rely on genetic testing. Since over 80 genes have been associated with IBMFSs and might be affected by different types of DNA aberrations, the best strategy to establish a diagnosis in a timely and cost effective manner is unknown. The aims of this study were to evaluate the role of genome-wide copy number variant (CNV) analysis in unraveling causal genetic alterations in IBMFS patients with unknown genotype and determine whether correlation exists between large CNVs and more severe phenotype. Methods. Patients from the Canadian Inherited Marrow Failure Registry (CIMFR) who were genetically investigated were included in this analysis. Genetic and clinical data were extracted and analyzed. Mann-Whitney test and Fisher's exact test were used to assess statistical significance. Results. Among 328 patients from the CIMFR who underwent molecular investigation, a causal genotype was identified in 185 cases (56.4%). 69 patients had genome-wide CNV analysis by SNP/CGH arrays, among which ten (14.5%) had positive results. In four out of ten cases who were genotyped by SNP/CGH array, genome-wide CNV analysis was critical for establishing the diagnosis. Among 308 patients who were tested for nucleotide-level mutations by either targeted gene analysis or next generation sequencing panels, casual mutations were found in 169 (54.9%). Three patients had compound heterozygosity for a CNV and nucleotide-level mutation. To determine whether large deletions are correlated with more severe phenotype we included nine additional patients with causal CNVs whose genotype was identified by MLPA (n=1), targeted FISH (n=1), DNA-qPCR analysis (n=1), Southern blotting (n=1) or metaphase cytogenetics (n=5). The causal CNVs among patients in our cohort ranged from 0.02 to 145.5 Mb in size. The most common disease associated with causal CNVs was Diamond-Blackfan anemia (four patients). Patients with CNVs tended to have significantly more non-hematological organ system involvement (p=0.03), developmental delay (mean=56% vs. 28%, p=0.03) and short stature (mean=67% vs. 40%, p=0.04) than patients with nucleotide-level mutations. The difference remained significant when we compared all patients with mutations that are predicted to result in truncation or lack of protein from the respective allele (large CNV, nonsense, and indel/ frameshift) to patients with mutations that are predicted to be hypomorphic or affect function (splicing, indel/ inframe and missense). There was no correlation between CNVs and the severity of the hematological disease. Conclusions. Most patients with IBMFSs have nucleotide-level mutations. However, a significant proportion of patients without such mutations have large CNVs that are not efficiently detected by current nucleotide-level testing methods. Therefore, genome-wide CNV analysis should be considered in IBMFS cases, where nucleotide-level sequencing does not reveal the causal mutation. Patients with IBMFSs and large CNVs had more non-hematological organ system involvement, a higher prevalence of developmental delay and short stature. This might be related to an additional impact of the CNVs on other genes close to the affected IBMFS gene or the severe damaging effect of the CNVs. Disclosures Lipton: Teva: Consultancy, Research Funding; Ariad: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Novartis Pharmaceuticals: Consultancy, Research Funding.

Background/Objectives: Diamond Blackfan anemia (DBA) is an inherited disorder characterized by chronic hypoproductive anemia, physical malformations, and an increased risk of malignancies. At least 12 DBA genes have been identified, which include various ribosomal protein genes and the transcription factor GATA1. The aims of our study were (1) to identify the mutation spectrum of DBA patients, utilizing a cohort of patients enrolled on the Canadian Inherited Marrow Failure Registry (CIMFR) and (2) to determine whether specific hematological abnormalities, malformations, and outcomes are associated with specific mutations. Methods: Patients were enrolled on the CIMFR, which is a multicenter cohort study of inherited bone marrow failure syndromes (IBMFS). Genetic testing was performed using one or more of the following tests: Sanger sequencing, next generation sequencing (NGS) DBA gene panel, a comprehensive NGS IBMFS gene panel developed in our laboratory, or comparative genetic hybridization (CGH). Severity of the hematological disease was dichotomized according to a patient's requirement for chronic treatment: those who were maintained on corticosteroids, blood transfusions, or received a hematopoietic stem cell transplantation were considered to have a more severe phenotype than those who did not require hematological treatment. Chi-square tests with a Fisher's exact test correction were used to compare genetic groups with at least 5 patients on observed phenotypes. Results: 71 patients with DBA have been enrolled in our registry. A causal mutation has been identified in 36 of these patients, with the following rates: RPS19 (n=11), RPL11 (n=7), RPL5 (n=6), RPS26 (n=5), RPL35a (n=2), RPS24 (n=2), and one of each RPS7, RPS29, RPS17. Remarkably, a substantial number of patients in our population-based cohort (19.4%) had mild hematological phenotype requiring no therapy. Patients with RPL11 mutations tended to have a less severe DBA phenotype, while patients with RPS19 mutations tended to have a more severe phenotype (p=0.04). In terms of non-hematological malformations, we found no differences in cardiac, stature and craniofacial malformations across the groups compared (all p>0.1). However, patients with RPL5 mutations had significantly more hand malformations (p=0.02), and patients with RPS26 mutations had more genitourinary malformations (p=0.04). To control for the impact of mutation severity on the observed phenotype, we compared the prevalence of mutations that are predicted to result in truncated or lack of protein from the respective allele (large copy-number variation, nonsense, or indel frameshift) to mutations that are predicted to be hypomorphic or affect function (splicing, indel/inframe and, missense) between mutation categories. There were no differences among genetic groups in the severity of their mutations (p=0.58). Conclusions: Mutations in a wide spectrum of ribosomal protein genes underlie DBA cases in Canada, which approximate those observed by other registries in Western countries. Patients with DBA caused by RPL11 mutations tended to have a milder hematological phenotype, while patients with RPS19 mutation tended to have a more severe phenotype. Mutations in RPS26 and RPL5 are associated with genitourinary and hand malformations, respectively. Our findings may help improve counseling of DBA patients and their family. Future studies are needed to replicate our results and determine whether these findings can help personalize care. Disclosures Lipton: Ariad: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Teva: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Novartis Pharmaceuticals: Consultancy, Research Funding.

THE CASE: A 10-year-old previously well boy presented with a 5-day history of constant epigastric abdominal pain not associated with meals. He had had 3 melena stools and 2 episodes of non-bilious, non-bloody emesis. He reported no NSAID use, weight loss or fever and had no history of excessive

Introduction: Inherited bone marrow failure syndromes (IBMFS) are characterized by single or multi-lineage cytopenias as well as non-hematologic manifestations. Hematopoietic stem cell transplantation (HSCT) is the only curative therapy for the hematological abnormalities. However, high rates of mortality and morbidity from this procedure have been reported in patients with IBMFSs. Objective: The study aim was to investigate the impact of patient, donor and treatment-related variables on the outcome of HSCT in IBMFS patients. Methods: Data of patients who were prospectively enrolled in the Canadian Inherited Marrow Failure Registry (CIMFR) from 2001 to 2012 and underwent HSCT were analyzed. The CIMFR is a population-based multicenter study, which includes all 16 pediatric tertiary care centers across all provinces in Canada. These centers care for >95% of the eligible pediatric IBMFS population in Canada. Descriptive analyses, as well as univariate and multivariate analyses (using a Cox proportional hazards model) were performed to assess the impact of multiple factors on probability of survival following transplant. Results: Among 363 patients enrolled in CIMFR, 65 underwent allogeneic HSCT. Thiry-four patients were male and 30 were female (gender unknown for 1 patient). Median age at diagnosis with IBMFS was 3.0 years (range: prenatal diagnosis to 32.0 years) and median age at HSCT was 6.5 years (range: 0.25-20.1 years). Median follow-up time post-HSCT (time to death or last follow-up) was 2.8 years (range 0.01–15.9 years). Indications for transplant included severe cytopenia (n=44), myelodysplastic syndrome (n=18) acute myeloid leukemia (n=2) and unavailable cause (n=1). Cell type were bone marrow (n=40), cord blood (n=17), peripheral blood (n=5), unknown (n=3). Sixty-two percent of patients (n=40) received cells from an unrelated donor. Seventy-four percent (n=47) of patients had a full HLA-matched donor; 19 of those were related and 28 were unrelated donors. The most common conditioning regimen combined high dose cyclophosphamide, fludarabine and anti-thymocyte globulin (n=17). Incidence of graft failure, acute (grade II-IV) graft versus host disease (GVHD) and chronic GVHD was 14%, 30% and 22%, respectively. Five-year probability of survival for HSCT recipients was 73.4% ± 6.1% (SE). Causes of death included infections (CMV, fungal infections and bacterial), GVHD, lymphoproliferative disorder and congestive heart failure, pulmonary fibrosis, bronchiolitis obliterans. In the univariate analysis, factors significantly associated with increased mortality post-HSCT included ≥20 pre-HSCT platelet transfusions, pre-transplant administration of granulocyte colony-stimulating factor, 1 or more HLA mismatches, donor type (divided into four categories: matched related, partially matched related, matched unrelated, partially matched unrelated) and conditioning regimens combining high doses of cyclophosphamide with fludarabine and anti-thymocyte globulin (while comparing this combination against all others). The former 3 variables remained significant in the multivariate analysis. Conclusion: Number of pre-transplant platelet transfusions, use of granulocyte colony-stimulating factor and one or more donor-recipient HLA mismatches were shown to increase the risk of mortality in patients with IBMFSs undergoing HSCT. Novel strategies are needed to improve outcome in patients with a high risk of HSCT-related complications. Disclosures No relevant conflicts of interest to declare.

Background and Objectives. Phenotypic overlap among the inherited bone marrow failure syndromes (IBMFSs) frequently limits the ability to establish a diagnosis based solely on clinical manifestations. Since a large number of IBMFS genes (>70) have been identified, genetic testing is often prolonged and costly. Correct diagnosis, care and counseling often depend on identifying the mutated gene. Thus time-efficient and cost-effective strategies for genetic testing are essential. The aims of this study were to develop and evaluate the application of a next generation sequencing (NGS) IBMFS Gene Panel assay for genetic testing of patients with previously characterized categories of IBMFSs (e.g. Fanconi anemia and Diamond Blackfan anemia) but unknown genotype, as well as patients with unclassified IBMFSs. Methods. We designed a NGS assay to test a comprehensive panel of 72 known IBMFS genes. Genomic DNA from patients enrolled on the Canadian Inherited Marrow Failure Registry was analyzed using the Haloplex technology and Illumina Seq2000 platform. The average gene coverage was 99.12%. SureCall program was used to align, map, and identify variants. Polyphen, Sift and MutationTaster were used to predict the effect of variants on the protein. Human Splicing Finder program was used to analyze effect of splicing. The assay was validated by detecting all 50 mutations and polymorphic variants that were previously found by Sanger sequencing in 31 patients. Results. A total of 158 patients with unknown mutations were studied. Among 75 patients with known categories of IBMFSs but unknown genotypes, we found deleterious mutations in 43 patients (57.3%). These categories included Diamond Blackfan anemia, Fanconi anemia, dyskeratosis congenita, Shwachman-Diamond syndrome, TAR syndrome, familial thrombocytopenia and Kostmann/severe congenital neutropenia. Among 83 patients with unclassified IBMFSs, we found deleterious mutations and established the diagnosis in 16 patients (19.2%). Established diagnoses included dyskeratosis congenita, Diamond-Blackfan anemia, myelokathexis, GATA2-associated familial MDS, WAS-associated severe congenital neutropenia, G6PC3-associated severe congenital neutropenia, MYH9-associated disorder, MASTL-associated disorder and Wiskott-Aldrich syndrome. All identified mutations were validated. The assay allowed identification of mutant genes that had not been previously reported to be associated with the patient phenotypes in two cases. The assay led to amendment of established diagnoses in two other cases. The assay results directed a change in clinical care in multiple cases, including implementation of cancer surveillance program and consideration for prenatal diagnosis. The cost of the NGS was $470/patient compared to $4643/patient among those who underwent genetic testing by Sanger sequencing during the tenure of the study. Conclusion. Our novel assay is a rapid, accurate, and cost saving strategy for genetic investigation of patients with IBMFSs. It can identify mutations in classified and unclassified IBMFSs with high level of sensitivity and precision. Disclosures No relevant conflicts of interest to declare.

In preparation for ovulation, paracrine communication between the preovulatory follicle and overlying theca/stromal cells and ovarian surface epithelium (OSE) must take place to facilitate the degradative and apoptotic events associated with ovulation. Kit tyrosine kinase receptors and their ligand, kit ligand (KL) are expressed within ovarian follicles, and ligand-induced receptor activation appears to account for some of the cell - cell interactions important for oocyte development. We investigated the expression of Kit receptors and KL in OSE cells and the possibility that modulation of their expression could affect OSE cell activity. KL mRNA and protein were detected in the OSE cell layer of rat ovaries, and primary cultures of rat OSE as well as the immortalized rat OSE cell line, ROSE 199, expressed KL, but not Kit receptors. Both primary and immortalized OSE cells preferentially expressed KL-1, rather than KL-2, transcripts, suggesting that these cells produce predominantly the soluble form of KL. Activation of the cAMP signalling pathway using dibutyryl cAMP decreased proliferation of ROSE 199 cells and elicited a threefold increase in KL expression. TGF-beta similarly inhibited ROSE 199 cell proliferation, but strongly inhibited dibutyryl cAMP-induced KL expression, indicating that changes in KL expression were not directly associated with OSE cell proliferation. The expression of mostly soluble KL in the surface epithelium suggests that this cytokine may be acting in a paracrine fashion, perhaps interacting with nearby Kit receptor-bearing theca cells.

To the Editor: We read with interest the article by Schoot et al. [1] regarding the challenge of accrual in supportive care trials in pediatric oncology. The authors outlined three main factors that influence accrual in these types of studies. Firstly, study and patient enrollment can be improved by having a dedicated clinician and research nurse at the center; secondly adequate and tailor-made information available for participants to make a well informed decision; and thirdly sufficient time available for participants to make their decision about participation. We just completed a pilot study collecting quality of life and pain data as well as a medication diary for 7 days following lumbar puncture procedure in children. In finishing this pilot study, we encountered a very poor completion rate. Parents were approached on the day their child was to have a lumbar puncture and asked to participate in the study. The study then involved the parents and child completing a quality of life assessment on the day of enrollment and 7 days post-enrollment, a pain assessment daily for 7 days, and a medication diary for 7 days. All of these assessments were completed at home and mailed back or brought back at their next appointment. Eleven families were approached and asked to participate in this study. One family declined to participate as they felt too overwhelmed, but ten families consented to participate and were given all the forms to complete after the procedure. Thus, accrual to this study was good. The families were also given a postage paid envelope to mail back the completed forms. The ten participants returned only five sets of forms. Thus, the problemwe encountered was poor form completion. That being said, those that were returned were completely filled in, with no missing documentation. As well, a comment from one of the participating parents was that by asking questions about pain and quality of life, this study opened communication from the child about fears they had but had not previously expressed. We feel that of the three factors outlined by Schoot et al. [1], two of the three were followed. Participants were given detailed information to make a decision about participation and there was a great deal of time available for participants to make their decision about participation. The participants were approached 2–3 h prior to their procedure, and between the time of being approached, and decision to participate; they were sitting in the clinic waiting for their procedure with no other interruptions of their time. They were given a detailed consent form as well as the opportunity to ask any questions they may have about the study. The main reason we can identify for the poor completion rate was the lack of a dedicated research nurse. There were no follow-up phone calls or electronic reminders to complete the study or to return the forms at their next visit, which has been shown in a recent review to improve recruitment to randomized controlled trials [2]. In our study, this would likely have improved the completion rate and will be utilized with our follow up study. Overall, Schoot et al. [1] provide an excellent overview of the challenges of accrual in supportive care trials in pediatric oncology and their article gives excellent guidelines to overcome these challenges in future studies.

Abstract 1266 Introduction: Inherited bone marrow failure syndromes (IBMFSs) are a group of rare, genetic disorders with a risk of clonal and malignant myeloid transformation including clonal marrow cytogenetic abnormalities, myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). The clinical characteristics and outcome of IBMFS-related clonal and malignant myeloid transformation are unclear, particularly in cases of early transformation such as isolated clonal marrow cytogenetic abnormalities. Objectives: The aims of this study were to determine the risk and clinical outcome of IBMFS-related clonal and malignant myeloid transformation using data from the Canadian Inherited Marrow Failure Registry (CIMFR). Methods: The CIMFR is a multicenter collaborative study which is intended to enroll all patients with IBMFSs in Canada. The registry was approved by the Institutional Ethics Board of all the participating institutions, and includes 15 of 16 pediatric tertiary care centers across all provinces in Canada. We estimate that these centers care for >95% of the eligible pediatric IBMFS population in Canada. The CIMFR is population-based as >90% of the patients in this study are from centers who enrolled >80% of the patients in their institutions. Clonal and malignant myeloid transformation was defined as having either clonal marrow cytogenetic abnormalities or prominent bi-lineage morphologic dysplasia or increased percentage of marrow blasts (≥5%) or a combination of the above. Results: Among 327 IBMFS patients enrolled on the CIMFR, 45 (13.8%) developed clonal and malignant myeloid transformation. In these 45 patients, the three most common IBMFS diagnoses were Fanconi anemia (31.1%), Shwachman-Diamond syndrome (20.0%) and unclassifiable IBMFSs (28.9%). Clonal marrow cytogenetic abnormalities were identified in 38/45 (84.4%) patients, while 5/45 (11.1%) patients had constitutional cytogenetic changes, 1/45 patients had AML with no cytogenetic abnormalities and 1/45 patients had no cytogenetic abnormalities. Two out of the 5 patients with constitutional cytogenetic abnormalities developed a clonal marrow cytogenetic abnormality later in their disease course. The most common clonal marrow cytogenetic abnormality was monosomy 7, which was found in 14/38 (36.8%) patients. Cytology in the majority of patients 20/45 (44.4%) was consistent with refractory cytopenia. Eight out of the 45 patients developed AML and 2 of these patients had monosomy 7. Twenty-two out of 45 (48.9%) patients with clonal and malignant myeloid transformation underwent hematopoietic stem cell transplantation due to severe cytopenia, excess blasts or leukemia. Fourteen out of the 22 (63.6%) transplanted patients are alive at last follow-up. Out of 8 patients who had AML, 3 received transplant and are alive at last follow-up. The 5 remaining AML patients died; 3 while awaiting transplant, 1 did not achieve remission and 1 refused transplant. Overall mortality in the group of patients with clonal and malignant myeloid transformation was 15/45 (33.3%) at a median follow-up of 10 months from diagnosis with clonal and malignant myeloid transformation. Overall mortality in those 282 patients on CIMFR without clonal and malignant myeloid transformation is 6.4%. Conclusion: Despite short-term follow-up of patients on the CIMFR, a relatively high prevalence of clonal and malignant myeloid transformation was found. Clonal marrow cytogenetic abnormalities are associated with a high risk of progression into advanced MDS or AML and death. Disclosures: No relevant conflicts of interest to declare.