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Key Points HMB is associated with rare and common variants in genes related to anemias and bleeding disorders.These are the first exome-sequencing results from patients with HMB, as well as their comparison with control exomes., Visual Abstract, Adolescents with low von Willebrand factor (VWF) levels and heavy menstrual bleeding (HMB) experience significant morbidity. There is a need to better characterize these patients genetically and improve our understanding of the pathophysiology of bleeding. We performed whole-exome sequencing on 86 postmenarchal patients diagnosed with low VWF levels (30-50 IU/dL) and HMB and compared them with 660 in-house controls. We compared the number of rare stop-gain/stop-loss and rare ClinVar “pathogenic” variants between cases and controls, as well as performed gene burden and gene-set burden analyses. We found an enrichment in cases of rare stop-gain/stop-loss variants in genes involved in bleeding disorders and an enrichment of rare ClinVar “pathogenic” variants in genes involved in anemias. The 2 most significant genes in the gene burden analysis, CFB and DNASE2, are associated with atypical hemolytic uremia and severe anemia, respectively. VWF also surpassed exome-wide significance in the gene burden analysis (P = 7.31 × 10−6). Gene-set burden analysis revealed an enrichment of rare nonsynonymous variants in cases in several hematologically relevant pathways. Further, common variants in FERMT2, a gene involved in the regulation of hemostasis and angiogenesis, surpassed genome-wide significance. We demonstrate that adolescents with HMB and low VWF have an excess of rare nonsynonymous and pathogenic variants in genes involved in bleeding disorders and anemia. Variants of variable penetrance in these genes may contribute to the spectrum of phenotypes observed in patients with HMB and could partially explain the bleeding phenotype. By identifying patients with HMB who possess these variants, we may be able to improve risk stratification and patient outcomes.

Cold storage of blood for 5 to 6 weeks has been shown to impair endothelial function after transfusion and has been associated with measures of end-organ dysfunction. Although the products of hemolysis, such as cell-free plasma hemoglobin, arginase, heme, and iron, in part mediate these effects, a complete analysis of transfused metabolites that may affect organ function has not been evaluated to date. Blood stored for either 5 or 42 days was collected from 18 healthy autologous volunteers, prior to and after autologous transfusion into the forearm circulation, followed by metabolomics analyses. Significant metabolic changes were observed in the plasma levels of hemolytic markers, oxidized purines, plasticizers, and oxidized lipids in recipients of blood stored for 42 days, compared with 5 days. Notably, transfusion of day 42 red blood cells (RBCs) increased circulating levels of plasticizers (diethylhexyl phthalate and derivatives) by up to 18-fold. Similarly, transfusion of day 42 blood significantly increased circulating levels of proinflammatory oxylipins, including prostaglandins, hydroxyeicosatrienoic acids (HETEs), and dihydroxyoctadecenoic acids. Oxylipins were the most significantly increasing metabolites (for 9-HETE: up to ∼41-fold, P = 3.7e-06) in day 42 supernatants. Measurements of arginine metabolism confirmed an increase in arginase activity at the expense of nitric oxide synthesis capacity in the bloodstream of recipients of day 42 blood, which correlated with measurements of hemodynamics. Metabolic changes in stored RBC supernatants impact the plasma metabolome of healthy transfusion recipients, with observed increases in plasticizers, as well as vasoactive, pro-oxidative, proinflammatory, and immunomodulatory metabolites after 42 days of storage.

Introduction: Low von Willebrand factor (VWF) activity is prevalent in adolescents with heavy menstrual bleeding (HMB). There is a need to better genetically characterize these patients and improve our understanding of the pathophysiology of their bleeding risk. Methods: One of the main objectives of this multi-center, single arm, observational cohort study was to genotype adolescent females with HMB and low VWF (≥ 30 and ≤ 50 IU/dL) by means of whole exome sequencing (WES), to identify variants throughout the exome that may modulate risk for bleeding. Post-menarchal females < 21 years with HMB (defined as PBAC score >100) and low VWF were eligible for the study. All patients were enrolled by participating centers where blood samples were collected. Exome data for 86 cases and 900 unrelated pediatric (0.8, GQ>20, AB between 0.3-0.7 and min DP>8. Case/control analyses included common and rare SNP associations, gene burden analysis of both rare nonsynonymous variants and ClinVar 'pathogenic' variants, and gene-set burden analyses. Variants were considered rare if they had a minor allele frequency of Results: Of the 113 subjects enrolled, 86 had sufficient blood samples collected for WES. The median age was 16.2 years (range: 11.5-19.6). 36% of cases showed variants in VWF vs. 26% of controls (p=0.14). After multiple test correction, WES revealed a significant common variant association in FERMT2 with an LD block with a frequency of 24% in cases and 6% in controls (p=7.5x10-7). Rare variant analysis showed a significant association with an intronic variant in ABCA13 (p=1.6x10-7). Among the gene burden analysis using rare nonsynonymous variants, 2 genes of interest passed multiple test correction: IL12B and DTNBP1. When using ClinVar 'pathogenic' variants as the input for the gene burden analysis, 4 genes of interest passed multiple test correction: HBM, MYLK, RUNX1 and CD36. Gene-set burden analysis revealed 5 significant pathways of interest, including platelet degranulation, platelet alpha granule lumen and erythrocyte differentiation. We then focused a subset of known risk genes and compared the number of missense, nonsense and ClinVar 'pathogenic' variants between cases and controls. GP6, and MTHFR had significantly more missense variants in controls vs. cases (p=0.003 and 0.01, respectively), and F13B approached significance, with more missense variants in controls than cases (p=0.07). Conclusion: We found VWF variants in 36% of subjects, in accordance with previous reports. We found novel SNP associations with variants in FERMT2 and ABCA13.FERMT2 encodes for the integrin, Kindlin 2, which has been shown to be critical for supporting vascular integrity. Several other relevant genes passed multiple test correction in gene burden analyses, including genes known to cause Hermansky-Pudlak syndrome (DTNBP1), familial platelet disorder (RUNX1), platelet glycoprotein IV deficiency (CD36) and aortic aneurysm (MYLK). This association with platelet disorders was strengthened by our gene-set burden results, which implicate several platelet-related pathways. These data suggest that while a subset of HMB patients may have their bleeding explained by variants in VWF, there is a role for other hemostasis, platelet biology and vascular integrity related gene variants which can contribute to the variation in bleeding severity in adolescents with low-VWF related HMB. Study supported by an investigator-initiated research grant from Shire US Inc., now part of Takeda Disclosures O'Brien: Bristol Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees. Mullins:Takeda, Bayer: Other: Advisory Board. Sidonio:Takeda: Research Funding. Ragni:Sangamo: Consultancy, Research Funding; Takeda: Research Funding; Bioverativ: Consultancy, Research Funding; Spark: Consultancy, Research Funding; BioMarin: Consultancy, Research Funding; Alnylam/Sanofi, ATHN, BioMarin, Bioverativ, Sangamo, Spark: Research Funding; Alnylam/Sanofi, BioMarin, Bioverativ, Spark: Consultancy; Alnylam Pharmaceuticals Inc., Baxalta/Takeda, BioMarin, Bioverativ, and Spark Therapeutics: Membership on an entity's Board of Directors or advisory committees; American Thrombosis Hemostasis Network: Other: Committee work; Baxalta/Takeda, CSL Behring, Genentech, a member of the Roche Group, OPKO Biologics, and Vascular Medicine Institute: Research Funding. Kulkarni:Sanofi/ Bioverativ, Bayer, Biomarin, Shire/Takeda, Novo Nordisk, Freeline: Other: clinical trial research grants ; Bioverativ/Sanofi, BPL, Genentech, Kedrion, Novo Nordisk, Octapharma, Pfizer, Takeda, Catalyst Bioscience Bayer: Membership on an entity's Board of Directors or advisory committees. Srivaths:Shire US Inc., now part of Takeda: Research Funding.

Bioenergetic dysfunction, although central to the pathogenesis of numerous diseases, remains uncharacterized in many patient populations because of the invasiveness of obtaining tissue for mitochondrial studies. Although platelets are an accessible source of mitochondria, the role of bioenergetics in regulating platelet function remains unclear. Herein, we validate extracellular flux analysis in human platelets and use this technique to screen for mitochondrial dysfunction in sickle cell disease (SCD) patients, a population with aberrant platelet activation of an unknown mechanism and in which mitochondrial function has never been assessed. We identify a bioenergetic alteration in SCD patients characterized by deficient complex V activity, leading to decreased mitochondrial respiration, membrane hyperpolarization, and augmented oxidant production compared with healthy subjects. This dysfunction correlates with platelet activation and hemolysis in vivo and can be recapitulated in vitro by exposing healthy platelets to hemoglobin or a complex V inhibitor. Further, reproduction of this dysfunction in vitro activates healthy platelets, an effect prevented by attenuation of mitochondrial hyperpolarization or by scavenging mitochondrial oxidants. These data identify bioenergetic dysfunction in SCD patients for the first time and establish mitochondrial hyperpolarization and oxidant generation as potential pathogenic mechanism in SCD as well as a modulator of healthy platelet function.

Introduction: Glanzmann thrombasthenia (GT) is a rare bleeding disorder (~1:1,000,000) caused by impaired function of platelet glycoprotein IIb/IIIa responsible for aggregation. This novel survey was designed to identify the burden of GT through better understanding of the management of the disorder and its psychosocial impact on patients and caregivers. Methods: Participants were recruited via a rare disease specialty recruiter from Comprehensive Health Education Services. Data were collected from January 31 through March 12, 2019, via a moderator-assisted online survey. On average, the survey was completed within 45 minutes. Information regarding demographics, diagnosis, treatment history, and quality of life was collected. Results: In total, 45 respondents (24 patients and 21 caregivers; 58% female) completed the survey. Many patients were born with significant bruising (76%) or bled extensively during circumcision (47%). As a result of their early symptoms, more than 50% of those surveyed were diagnosed prior to their first birthday. For others, the average time between experiencing initial symptoms and visiting a specialist was just over 1 year and to diagnosis was just over 2 years (average age, 2.6 years, range Conclusions: Many patients with GT are identified early in life owing to a severe phenotype, but diagnosis remains somewhat difficult. Patients with GT experience frequent bleeding episodes, commonly as bruises and nosebleeds, with 31% experiencing more than 100 bleeds per year. Additional support from outside the GT patient community is needed. Patients desire additional education for themselves and their HCPs, especially around menstruation, childbearing, and treatment options. Disclosures Duncan: Novo Nordisk Inc: Consultancy. Kellum:Novo Nordisk Inc: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Jain:Bioverativ/Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novo Nordisk Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; CSL Behring: Consultancy, Membership on an entity's Board of Directors or advisory committees; Octapharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda/Shire: Consultancy, Membership on an entity's Board of Directors or advisory committees; BPL: Consultancy, Membership on an entity's Board of Directors or advisory committees. Peltier:Novo Nordisk Inc: Membership on an entity's Board of Directors or advisory committees. Cooper:Novo Nordisk Inc.: Employment. Saad:Novo Nordisk Inc: Employment.

61st Annual Meeting and Exposition of the American-Society-of-Hematology (ASH) -- DEC 07-10, 2019 -- Orlando, FL, WOS:000577160400199, [No Abstract Available], Amer Soc Hematol

Introduction: Low Von Willebrand factor (VWF) activity, considered a bleeding risk factor, is prevalent in some adolescents with heavy menstrual bleeding (HMB), wherein upfront hemostatic therapy may not be readily considered. There is a need to better define this patient subset phenotypically and genotypically, to stratify their risk to bleed, and to tailor their therapy in hopes of preventing complications. In adolescents with HMB and low VWF, we hypothesized that a significant proportion will have disease-causing sequence variations in the VWF gene and/or modifier genes that affect hemostasis, thrombosis or vascular biology, and these will correlate with their bleeding phenotype. Methods: The objectives of this multi-center, single arm, observational cohort study were to 1) study the genotype of adolescent females with HMB and low VWF (≥ 30 and ≤ 50 IU/dL), 2) correlate genotype with bleeding phenotype by Pictorial Blood Assessment Chart (PBAC) score and ISTH bleeding assessment tool (BAT) score. Post-menarchal females < 21 years, with HMB (defined as PBAC score >100) and low VWF were eligible for the study. Patients who did not meet these criteria or diagnosed with other bleeding disorders were ineligible. Members of the Foundation for Women and Girls with Blood Disorders are participating centers in the study. Clinical phenotype data including HMB characteristics, PBAC, BAT, response to desmopressin challenge, management details, clinical outcomes, and laboratory values were obtained. Blood samples were collected for analysis of a 142 gene array that includes VWF, genes involved in hemostasis, thrombosis and vascular biology. DNA sequencing of all exons and intron/exon boundaries was performed; variants were called presumably pathogenic if categorized as damaging by the pipeline with allele frequency Results: 63 subjects were enrolled to date; 1 subject was later found to be ineligible due to detection of another bleeding disorder. The mean age was 16 years (range 11.5-20.2). The median BAT score was 5.0 (N=61; 2-20), median PBAC score was 481 (N=62; 114-8150). 11/48 (23%) had hemoglobin Conclusion: Our study confirms the feasibility of a multi-center study in adolescent females with HMB and low VWF. All subjects had significant bleeding phenotype with elevated BAT and PBAC scores, with complications including anemia, iron deficiency, transfusion requirement, and hospitalization. Response to DDAVP challenge in subjects tested was good and sustained. Potential pathogenic gene variants, not only in VWF, but also in CF and PLT genes were found in 51% of the subjects, which may account for their bleeding phenotype. The separate or the combined presence of VWF, PLT and CF damaging gene variants does not appear to correlate with the subjects' bleeding severity in this interim analysis. A larger sample size and further analysis of gene variants may provide more information regarding the phenotype/genotype correlation in this patient population. Study supported by an investigator-initiated research grant from Baxalta US Inc., now part of Shire Disclosures Srivaths: Shire: Research Funding. Kulkarni:Bioverativ: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; NovoNordisk: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Octa Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Kedrion: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genetech: Honoraria, Membership on an entity's Board of Directors or advisory committees; BPL: Honoraria, Membership on an entity's Board of Directors or advisory committees. Mullins:Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees. Ragni:Sangamo: Research Funding; Bioverativ: Consultancy, Research Funding; Shire: Research Funding; Alnylam: Membership on an entity's Board of Directors or advisory committees, Research Funding; SPARK: Consultancy, Research Funding; Biomarin: Membership on an entity's Board of Directors or advisory committees, Research Funding; MOGAM: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Research Funding; Novo Nordisk: Research Funding. Kouides:Octapharma: Research Funding; UniQure: Other: DSMB.

Life expectancy for people with hemophilia has improved and is now approaching that of the general population. This growing population will likely experience age-related co-morbidities such as cardiovascular diseases, diabetes, and chronic kidney disease. Distribution of endogenous and exogenous (plasma or recombinant) factor IX between the intravascular and extravascular spaces have not been fully elucidated. In vivo recovery and elimination half-life have been suggested to be inadequate descriptors of effective pharmacokinetics (PK) of FIX, but that differences in distribution might be clinically important (Bjorkman Haemophilia 2013). Pharmacokinetics (PK) of the long acting recombinant Factor IX albumin fusion protein (rIX-FP) with albumin demonstrated improved PK in a pivotal trial. However, no data exists in patients with end stage renal failure requiring dialysis. We present PK data for a single patient on dialysis who has received a single dose of rIX-FP, Case: 71 y/o male with moderate hemophilia B with factor IX activity levels ranging between 2-4%. He averaged 2 bleeds per year until 2013, when his creatinine increased to 1.93-2.3 (GFR approx. 30mL/min). He averaged 2-4 joint or soft tissue bleeds since 2013. His GFR dropped to 7-10 mL/min in 2015. He tested negative for HCV, HIV, and multiple myeloma. A kidney biopsy and angiogram was not performed. He had nephrotic range proteinuria. His renal ultrasound was unremarkable. Hypertensive nephrosclerosis was the working diagnosis. The patient had a central line placed and AV fistula created in April 2016, which was complicated by bleeding despite factor replacement with Benefix (Pfizer). He began hemodialysis in May 2016 using a tunneled central catheter while awaiting maturation. The patient wanted to switch to peritoneal dialysis (PD). For the PD catheter placement we recommended Idelvion for factor replacement and conducted a pharmacokinetic study. A dose of 100 IU/kg (10,879 units) was administered. Factor IX levels were drawn at 1 hour (h), 24 (h), 72 (h), 168 (h), 216 (h), and 336 (h), with factor IX activity levels of 91%, 59%, 34%, 18%, 16%, and 11% respectively. Dialysis occurred 2 (h), 4 days, 1 week, and 11 days during the 2 week PK study. Samples were analyzed with a one stage assay using a silica activator (PTT A Diagnostica Stago) on a Stago Evolution Conclusion: rIX-FP's demonstrated improved pharmacokinetic parameters in half-life, clearance and AUC in a recent study. To our knowledge, no data exist in patients with end-stage renal disease. We have presented data in a dialysis patient and show comparable PK parameters to that shown in the aforementioned study. Our patient's half-life (t1/2) was 165.2 (h) and AUC was 7663.5. It appears that dialysis and end-stage renal disease does not alter PK of rIX-FP. Further studies are needed in more hemophilia B patients with end-stage renal disease to confirm our findings. Disclosures Jain: Biogen: Speakers Bureau; Bayer: Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Honoraria.

Background. Heavy menstrual bleeding (HMB) is a frequent complaint in adolescence and is often multifactorial. Of the possible causes, anovulation is likely to be the most common reason but there is mounting evidence that bleeding disorders (BDs) are often an unidentified cause of HMB. Wide ranges of reported prevalence, difficulty in discerning normal from excessive menstrual bleeding and the semi-empiric use of hormonal therapy makes identifying BDs in adolescents challenging. Bleeding assessment tools (BATs) have been developed- primarily in the adults - to improve diagnostic accuracy, predict bleeding phenotype and describe symptoms. The International Society of Haemostasis and Thrombosis (ISTH) BAT was specifically designed to quantify bleeding symptoms that are pediatric specific. An ISTH-BAT score of > 3 for children is considered abnormal. The ISTH BAT has not yet been specifically tested in adolescents presenting with HMB. The objective of this study was to examine the diagnostic utility of ISTH-BAT bleeding score (BS) of > 3 as a predictor of BDs in adolescents with HMB. Methods. We prospectively analyzed clinical data on 70 adolescents without a known BD, referred for HMB, to the Adolescent, Gynecology and multidisciplinary Young Women's Blood Disorders Clinics at University of Texas Southwestern Medical Center from July 2014 to June 2016. This cohort is part of an ongoing prospective study investigating the incidence of BDs in adolescents with HMB (planned n=200). All subjects underwent a standardized comprehensive diagnostic approach, including the ISTH BAT to quantify bleeding symptoms accurately. The ISTH-BAT was applied by two trained investigators and any discrepancy in scores was settled by discussion. As per National Heart, Lung, and Blood Institute guidelines, VWF:Ag and/or VWF:RCo Results. The mean age of study participants was 14.4+1.8 years (range: 11-18 years). Twenty-eight out of 70 patients (40%) were found to have a BD; 8 met criteria for VWD, 12 had low VWF levels, 2 were hemophilia A carriers, 5 were diagnosed with inherited platelet dysfunction and 1 had inherited thrombocytopenia. The mean BS was higher in subjects with VWD (N=20) as compared to those without a BD (N=42) (4.5 +1.6, vs. 3.6+ 1.0, p= 0.02). At least one other bleeding symptom was present in 8 (40%) of the 20 girls with vWD. The most commonly reported bleeding symptoms were epistaxis (35%), oral (15%), cutaneous (10%) and post-surgical (5%). There was no difference in patterns of menstrual bleeding (anovulatory vs. ovulatory) between girls with and without a BD (55% ovulatory vs. 41% ovulatory, p-=0.28). ROC analysis of the ISTH-BAT bleeding scores showed that at a BS of > 3, the sensitivity of the ISTH BAT was 100% but specificity was only marginal at 2.4% with an accuracy of 41%, whereas at a BS of > 5, sensitivity, specificity and accuracy were 30%, 88.10% and 69%, respectively. ROC analysis showed area under the curve of 0.66 (CI: 0.52-0.80) indicating poor discrimination for the ISTH-BAT score in determining BD in girls with HMB. Conclusion. Our study is the first attempt to prospectively examine the applicability of using ISTH-BAT score as a screening tool to exclude the presence of BD in adolescent girls presenting with HMB. In this study cohort, ISTH-BAT bleeding score of > 3 demonstrated poor diagnostic accuracy in ruling out vWD. A score of > 5 had high specificity which can decrease false positive diagnosis and repetitive testing. Future data from the ongoing study will help understand how a combination of BATs and a laboratory testing algorithm can unravel hemostatic defects in adolescents with HMB. Disclosures Jain: Bayer: Membership on an entity's Board of Directors or advisory committees; Biogen: Speakers Bureau; Novo Nordisk: Honoraria. Sarode:CSL Behring: Consultancy, Honoraria. Journeycake:CSL: Consultancy; Biogen: Consultancy; Baxalta/Shire: Consultancy. Zia:NHLBI K23: Research Funding.

Introduction: Unpredictable, prolonged or heavy menstrual bleeding (HMB) is not unusual in many adolescents soon after menarche. Anovulation, owing to immaturity of the hypothalamic-pituitary-ovarian axis, is often the cause of HMB; however, it may coexist and mask an underlying bleeding disorder (BD). Retrospective data in adolescents with HMB suggest a prevalence of BDs from 10 to 62%. Prospective studies with uniform hemostatic evaluation and concurrent quality of life (QoL) assessments have not been performed. The incidence of BDs in adolescents, especially those with anovulatory bleeding, remains unknown. Methods: In this ongoing prospective cohort study (targeted n=200), 130 adolescents referred for HMB to multidisciplinary Young Women's Blood Disorders Clinics were enrolled. An assessment of menstrual loss using pictorial blood assessment chart (PBAC) and bleeding symptoms using ISTH-bleeding assessment tool (BAT) was undertaken. Participants underwent a comprehensive evaluation determined a priori, including assessment of hypermobility, standardized laboratory evaluation (prothrombin time, activated partial thromboplastin time, fibrinogen, thrombin time, von Willebrand disease (VWD) panel, whole blood platelet aggregation with ATP secretion, factor assays (FIX and FXIII), global hemostasis and hyperfibrinolysis using ROTEM, and a pelvic ultrasound (US). Patient reported outcomes for health related QoL(HR-QoL) was completed. Results: The mean age of participants was 14 (range 11-18) and mean age at menarche was 11.7 yrs. (range: 9-16). The mean PBAC score, before contraceptive initiation, was 504 (range: 100- 1200) and the mean ISTH BAT score was 3.8 (range: 1-8) in all participants. 62% had anovulatory menstrual bleeding. An inherited BD and/or bleeding risk was diagnosed in 24.6% (n=32); 9% (n=12) were diagnosed with VWD, 5% (n=6) with qualitative platelet dysfunction and 2 subjects were found to be hemophilia A (HA) carriers. Low VWF levels (VWF:Rco 30-50%) were detected in 9% (n=12). 15% had evidence of mild systemic hyperfibrinolysis (lysis 3-8% on ROTEM) but none met the criteria for further investigation for an inherited disorder of hyperfibrinolysis . Of those without BD, 2 were diagnosed to have VWF exon 28 polymorphism, and 3 were referred and ultimately diagnosed with hypermobility syndrome by Genetics. One was found to have endometriosis by laparoscopy and 3 were diagnosed with PCOS. Of those with BDs (all with low VWF), 3 were diagnosed with hypermobility syndrome (total 6) and 4 with PCOS (total 7). US was normal in all subjects. The PBAC scores were higher in BDs (634 vs. 410; SD ± 275 p=0.002), irrespective of the pattern of bleeding. No differences were found in the ISTH BAT scores (after excluding HA carriers) (3.6 vs. 4.8; SD ± 1.19, p=0.06), initial hbg or ferritin levels between the two groups. Only 6% (n=8) with BDs required ED visit and/or hospitalization for HMB vs. 14% (n=18) without a BD, of which majority had anovulatory bleeding. On multivariate logistic regression, no predictors of BDs were found. Adolescents with BDs had a decreased HR-QoL compared to those without a BD (QoL score 58 vs.87; SD± 12.5, p= Conclusions: Inherited BDs are common in adolescents with HMB, confer a decreased HR-QoL and can be associated with anovulatory bleeding. A comprehensive evaluation is required to unravel disorders causing HMB. In this ongoing study, at this time, no predictor of an inherited BD was found in adolescents with HMB. Data accrual from the fully powered, ongoing, prospective study may offer further data to develop an ideal tool with a scoring system to take into account all prevalent causes of HMB to accurately predict a BD in adolescents. Disclosures Zia: NHLBI K23: Research Funding. Journeycake:CSL: Consultancy; Biogen: Consultancy; Baxalta/Shire: Consultancy. Jain:Novo Nordisk: Honoraria; Bayer: Membership on an entity's Board of Directors or advisory committees; Biogen: Speakers Bureau. Sarode:CSL Behring: Consultancy, Honoraria.

Abstract 2030 Sickle cell disease (SCD) is associated with a high rate of thromboembolic complications, particularly in patients with advanced vasculopathy. Recent functional studies have revealed pathological platelet activation associated with intravascular hemolysis, the severity of pulmonary hypertension (PAH), and impaired NO-signaling in platelets mediated by NO scavenging by plasma hemoglobin (Villagra J et al, Blood 2007; Hu W et al, Blood 2010, prepublished online). In addition, our previous amplified platelet transcriptome studies in SCD patients have demonstrated dysregulated arginine and polyamine metabolism, potentially contributing to this dysfunction at the transcriptional level (Raghavachari N et al, Circulation 2007). New RNA technologies for purification of total RNA including small RNAs now allow for more refined study of transcriptional events in platelets from individual patients. We have undertaken the present study to demonstrate and validate the presence and differential expression of microRNAs (miRNAs) in platelets from patients with SCD compared with African American control subjects. We hypothesize that posttranscriptional regulation of the platelet function by miRNAs is an important contributor to SCD pathogenesis associated with pathological platelet activation. To date, there have been no studies undertaken to study the role of platelet miRNAs in SCD. Platelet rich plasma samples from 43 subjects were obtained from University of Pittsburgh Medical Center (UPMC) and National Heart, Lung, Blood Institute (NHLBI). Out of these there were 27 SCD patients and 17 were sex-, race- matched healthy controls. Out of the SCD patients, 18 were known to have PAH and 14 were on hydroxyurea (HU) at the time of study enrollment. Total platelet RNA including miRNAs were extracted using the miRNeasy Minikit (Qiagen, Valencia, CA) with yield in the range of 110–1875 ng from 16 ml of whole blood per donor. We hybridized these samples on a miRNA microarray platform (Agilent version 3) containing 866 human miRNAs. The array data was normalized using quantile normalization and were analyzed with GeneSpring GX 11 software. Differential expression profiles between sickle cell disease patients and controls were determined separately for the NHLBI and UPMC cohort to detect a greater than 2 fold difference change in miRNA expression at p-value of 0.05. Our final expression list included only common miRNAs identified in both cohorts, allowing for an additional level of validation. Final validation was performed by RT-PCR of a subset of the differentially expressed miRNAs. Our analysis identified 42 significantly differentially expressed miRNAs in platelets when comparing the SCD with the control groups, at a fold-change > 2 and p-value Disclosures: No relevant conflicts of interest to declare.