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Objective: We present prenatal diagnosis of Jacobsen syndrome associated with a distal 11q deletion and a distal 8q duplication by chromosome microarray analysis (CMA) in a fetus with multiple congenital anomalies on fetal ultrasound. Case Report: A 41-year-old, gravida 2, para 1, woman underwent amniocentesis at 25 weeks of gestation because of intrauterine growth restriction, endocardial cushion defect, clenched hands, arthrogryposis, rocker bottom feet and craniosynostosis on fetal ultrasound. Amniocentesis revealed a karyotype of 46,XX,add(11)(q23.3). Array comparative genomic hybridization (aCGH) analysis of the DNA extracted from the uncultured amniocytes revealed the result of arr 8q24.13q24.3 × 3, 11q23.3q25 × 1. Analysis of FGFR2 revealed no mutation. The karyotype was 46,XX,der(11)t(8;11)(q24.13;q23.3). The parental karyotypes were normal. The pregnancy was subsequently terminated, and a dead malformed fetus was delivered with craniofacial dysmorphism of low-set malformed ears, depressed nasal bridge, hypertelorism, small mouth, clenched hands and rocker bottom feet. Cytogenetic analysis of the placenta revealed a karyotype of 46,XX,der(11)t(8;11)(q24.13;q23.3). aCGH analysis of the DNA extracted from the umbilical cord showed the result of arr 8q24.13q24.3 (126,302,369–146,280,020) × 3.0, arr 11q23.3q25 (120,469,928–134,868,407) × 1.0 [GRCh37] with a 19.978-Mb duplication of 8q24.13-q24.3 and a 14.398-Mb deletion of 11q23.3-q25 encompassing the genes of BSX, ETS1, FLI1 and ARHGAP32. Conclusion: CMA is useful for detection of de novo chromosomal rearrangement in the fetus with multiple congenital anomalies on fetal ultrasound.

Introduction. Jacobsen syndrome (JS) is a rare genetic disease associated with the deletion of chromosome 11q, characterized by multiple malformations, hematological and immune disorders. The development of immunodeficiency in JS is often underestimated, which leads to recurrent infectious complications. Presentation of a clinical case. The article presents a clinical case of a patient with a deletion of chromosome 11q and combined immunodeficiency. Our patient had recurrent infections, cytopenic syndrome, combined immunodeficiency, as well as other clinical manifestations of Jacobsen syndrome. In addition to a decrease in serum immunoglobulins, a deep deficiency of the T-cell link of immunity with a low content of T-lymphocytes, recent emigrants from the thymus, has been established. Conclusions. The peculiarity of the presented clinical case is that with a relatively small amount of deletion 11q, the child realized a complete clinical phenotype of the disease and a deep combined immunodeficiency. The article was written to improve doctors’ knowledge about this rare form of congenital immunodeficiency.

Key Clinical Message: Recurrent severe respiratory infections in Jacobsen syndrome (JS) are unusual and should prompt evaluation of the immune system. A variety of immune defects have been reported in JS and intravenous immune globulin (IVIG) treatment reduces severe infections. [ABSTRACT FROM AUTHOR]

The article presents a literature review of chromosomal deletion syndrome – terminal deletion of the long arm of chromosome 11, Jacobsen syndrome, manifested by skeletal abnormalities, congenital heart defects, developmental delay, autism. The disease is of clinical interest in connection with a specific phenotype and life-threatening, but potentially curable conditions: bleeding and immunodeficiency. The analysis of informationally significant genes of the chromosome 11 deletion site is presented. A case report of a girl with Jacobsen syndrome with a follow-up history of up to 6 years is presented. In the observed case, previously unremarked symptoms were described: ataxia and retropulsion. The differential diagnosis and criteria for hypomyelination syndrome are also analyzed. Recommendations are given for the management of life-threatening conditions in patients in accordance with American protocols.

Key Clinical Message Recurrent severe respiratory infections in Jacobsen syndrome (JS) are unusual and should prompt evaluation of the immune system. A variety of immune defects have been reported in JS and intravenous immune globulin (IVIG) treatment reduces severe infections.

Hypoplastic left heart syndrome occurs in up to 3% of all infants born with congenital heart disease and is a leading cause of death in this population. Although there is strong evidence for a genetic component, a specific genetic cause is only known in a small subset of patients, consistent with a multifactorial etiology for the syndrome. There is controversy surrounding the mechanisms underlying the syndrome, which is likely due, in part, to the phenotypic variability of the disease. The most commonly held view is that the "decreased" growth of the left ventricle is due to a decreased flow during a critical period of ventricular development. Research has also been hindered by what has been, up until now, a lack of genetically engineered animal models that faithfully reproduce the human disease. There is a growing body of evidence, nonetheless, indicating that the hypoplasia of the left ventricle is due to a primary defect in ventricular development. In this review, we discuss the evidence demonstrating that, at least for a subset of cases, the chamber hypoplasia is the consequence of hyperplasia of the contained cardiomyocytes. In this regard, hypoplastic left heart syndrome could be viewed as a neonatal form of cardiomyopathy. We also discuss the role of the endocardium in the development of the ventricular hypoplasia, which may provide a mechanistic basis for how impaired flow to the developing ventricle leads to the anatomical changes seen in the syndrome.

Abstract Background Jacobsen syndrome is a rare genetic disorder with multiple congenital anomalies and platelet abnormalities caused by chromosome 11 deletion. Case presentation A 7-month-old boy with thrombocytopenia underwent ventricular septal defect closure. At the beginning of surgery, the platelet count was 168 × 103/μL, and heparinized kaolin with heparinase reaction time (HKH-R), which represents clot formation time, was prolonged at 30.4 min. Platelet transfusion was continued, and at the end of surgery, the platelet count and HKH-R values improved to 215 × 103/μL and 15 min, respectively. Conclusions As anesthetic management of patients with abnormal platelet function, the viscoelasticity test might be useful in evaluating hemostatic capacity.

Jacobsen syndrome (JS) is caused by the terminal deletion at the long arm of chromosome 11. It is characterized by growth retardation, intellectual disability, facial dysmorphism, and other congenital abnormalities. The subband 11q24.1 has been confirmed to be the critical region for the typical features of JS. The patient in the current study is a 2-year-old male child with prominent craniofacial abnormalities and congenital heart disease. High-resolution single-nucleotide polymorphism arrays revealed breakage in chromosome 11q beginning at 11q24.2, with complete deletion of the distal portion. We collected all available reports describing patients with breakages at 11q24.1 or 11q24.2, and compared it with the typical features of JS. We found that the phenotype of cleft lip and palate (CLP) was present in both groups of patients with no overlap region in the deletion region (between 11q21-q23 and 11q24.2-qter), which indicated that other genes may be related to CLP in JS. [ABSTRACT FROM AUTHOR]

Objective: Jacobsen syndrome is an infrequent contiguous gene syndrome that involves the deletion of the long arm of chromosome 11. It is mostly accompanied by intellectual disability and other abnormalities. The majority of the patients are hospitalized or lost within the first two years of life. Case: We report a case of a fetus at 21 weeks of gestation with Jacobsen syndrome who presented with a conotruncal cardiac defect. Amniocentesis was performed, and karyotype analysis revealed that there was a de novo deletion of chromosome 11. The family decided to terminate the pregnancy. Conclusion: Prenatal diagnosis of Jacobsen syndrome is not always possible, since the characteristic ultrasound findings vary greatly between patients. Additionally, existing symptoms and signs may not always be found with imaging techniques. However, if present, certain ultrasonographic findings should lead clinicians to consider the syndrome. The study aims to present a rare case of Jacobsen syndrome, inform the clinicians, and guide on this syndrome and its possible outcomes. [ABSTRACT FROM AUTHOR]

Jacobsen syndrome is a rare genetic disorder associated with a terminal deletion in chromosome 11. The clinical presentation is variable. Although immunodeficiency has been described in patients with Jacobsen syndrome, a clear genotype-phenotype correlation has not yet been established. Here, we report on the immunologic phenotypes of four patients with Jacobsen syndrome. All four patients showed one or more atypical immunologic features. One patient suffered from recurrent viral infections, two patients had experienced a severe bacterial infection and one had received antibiotic prophylaxis since early childhood. One patient had experienced severe, transient immune dysregulation. Hypogammaglobulinemia and low B cell counts were found in two patients, while the number of recent thymic emigrants (CD31+CD45RA+ CD4 cells) was abnormally low in three. When considering the six immune-related genes located within the affected part of chromosome 11 (ETS1, TIRAP, FLI1, NFRKB, THYN1, and SNX19), only the ETS1 gene was found be deleted in the three patients with low numbers of recent thymic emigrants and non-switched memory B cells. Our findings support the hypothesis whereby Jacobsen syndrome is associated with a combined immunodeficiency with variable presentation. Further investigations of potential genotype-phenotype correlations are warranted and might help to personalize patient management in individuals lacking immune-related genes. In addition, we recommend immunologic follow-up for all patients with Jacobsen syndrome, as immune abnormalities may develop over time. [ABSTRACT FROM AUTHOR]

Disorders of the long arm of chromosome 11 (11q) are rare and involve various chromosomal regions. Patients with 11q disorders, including Jacobsen syndrome, often present with a susceptibility for bacterial and prolonged viral and fungal infections partially explained by hypogammaglobulinemia. Additional T lymphocyte or granular neutrophil dysfunction may also be present. In order to evaluate infectious burden and immunological function in patients with 11q disorders, we studied a cohort of 14 patients with 11q deletions and duplications. Clinically, 12 patients exhibited prolonged and repetitive respiratory tract infections, frequently requiring (prophylactic) antibiotic treatment (n = 7), ear-tube placement (n = 9), or use of inhalers (n = 5). Complicated varicella infections (n = 5), chronic eczema (n = 6), warts (n = 2), and chronic fungal infections (n = 4) were reported. Six patients were on immunoglobulin replacement therapy. We observed a high prevalence of low B lymphocyte counts (n = 8), decreased T lymphocyte counts (n = 5) and abnormal T lymphocyte function (n = 12). Granulocyte function was abnormal in 29% without a clinical phenotype. Immunodeficiency was found in patients with terminal and interstitial 11q deletions and in one patient with terminal 11q duplication. Genetically, FLI1 and ETS1 are seen as causative for the immunodeficiency, but these genes were deleted nor duplicated in 4 of our 14 patients. Alternative candidate genes on 11q may have a role in immune dysregulation. In conclusion, we present evidence that inborn errors of immunity are present in patients with 11q disorders leading to clinically relevant infections. Therefore, broad immunological screening and necessary treatment is of importance in this patient group. [ABSTRACT FROM AUTHOR]

Objective: We present prenatal diagnosis of Jacobsen syndrome associated with a distal 11q deletion and a distal 8q duplication by chromosome microarray analysis (CMA) in a fetus with multiple congenital anomalies on fetal ultrasound., Case Report: A 41-year-old, gravida 2, para 1, woman underwent amniocentesis at 25 weeks of gestation because of intrauterine growth restriction, endocardial cushion defect, clenched hands, arthrogryposis, rocker bottom feet and craniosynostosis on fetal ultrasound. Amniocentesis revealed a karyotype of 46,XX,add(11)(q23.3). Array comparative genomic hybridization (aCGH) analysis of the DNA extracted from the uncultured amniocytes revealed the result of arr 8q24.13q24.3 × 3, 11q23.3q25 × 1. Analysis of FGFR2 revealed no mutation. The karyotype was 46,XX,der(11)t(8;11)(q24.13;q23.3). The parental karyotypes were normal. The pregnancy was subsequently terminated, and a dead malformed fetus was delivered with craniofacial dysmorphism of low-set malformed ears, depressed nasal bridge, hypertelorism, small mouth, clenched hands and rocker bottom feet. Cytogenetic analysis of the placenta revealed a karyotype of 46,XX,der(11)t(8;11)(q24.13;q23.3). aCGH analysis of the DNA extracted from the umbilical cord showed the result of arr 8q24.13q24.3 (126,302,369-146,280,020) × 3.0, arr 11q23.3q25 (120,469,928-134,868,407) × 1.0 [GRCh37] with a 19.978-Mb duplication of 8q24.13-q24.3 and a 14.398-Mb deletion of 11q23.3-q25 encompassing the genes of BSX, ETS1, FLI1 and ARHGAP32., Conclusion: CMA is useful for detection of de novo chromosomal rearrangement in the fetus with multiple congenital anomalies on fetal ultrasound., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article., (Copyright © 2024. Published by Elsevier B.V.)

Jacobsen syndrome is a rare genetic disorder associated with a terminal deletion in chromosome 11. The clinical presentation is variable. Although immunodeficiency has been described in patients with Jacobsen syndrome, a clear genotype-phenotype correlation has not yet been established. Here, we report on the immunologic phenotypes of four patients with Jacobsen syndrome. All four patients showed one or more atypical immunologic features. One patient suffered from recurrent viral infections, two patients had experienced a severe bacterial infection and one had received antibiotic prophylaxis since early childhood. One patient had experienced severe, transient immune dysregulation. Hypogammaglobulinemia and low B cell counts were found in two patients, while the number of recent thymic emigrants (CD31+CD45RA+ CD4 cells) was abnormally low in three. When considering the six immune-related genes located within the affected part of chromosome 11 (ETS1, TIRAP, FLI1, NFRKB, THYN1, and SNX19), only the ETS1 gene was found be deleted in the three patients with low numbers of recent thymic emigrants and non-switched memory B cells. Our findings support the hypothesis whereby Jacobsen syndrome is associated with a combined immunodeficiency with variable presentation. Further investigations of potential genotype-phenotype correlations are warranted and might help to personalize patient management in individuals lacking immune-related genes. In addition, we recommend immunologic follow-up for all patients with Jacobsen syndrome, as immune abnormalities may develop over time.

Background: Jacobsen syndrome is a rare genetic disorder with multiple congenital anomalies and platelet abnormalities caused by chromosome 11 deletion. Case presentation: A 7-month-old boy with thrombocytopenia underwent ventricular septal defect closure. At the beginning of surgery, the platelet count was 168 × 103/μL, and heparinized kaolin with heparinase reaction time (HKH-R), which represents clot formation time, was prolonged at 30.4 min. Platelet transfusion was continued, and at the end of surgery, the platelet count and HKH-R values improved to 215 × 103/μL and 15 min, respectively. Conclusions: As anesthetic management of patients with abnormal platelet function, the viscoelasticity test might be useful in evaluating hemostatic capacity. [ABSTRACT FROM AUTHOR]

Background: We report a case of the neonatal interstitial lung disease pulmonary interstitial glycogenosis in a girl with Jacobsen syndrome. While Jacobsen syndrome is caused by a deletion on the long arm of chromosome 11 and is genetically confirmed, pulmonary interstitial glycogenosis is of unknown etiology and is diagnosed by lung biopsy. Pulmonary interstitial glycogenosis has not previously been described in association with Jacobsen syndrome.Case Presentation: A term newborn small for gestational age Caucasian girl presented with respiratory distress, pulmonary hypertension, congenital heart defects, immunodeficiency, and thrombocytopenia. She was diagnosed with Jacobsen syndrome, but also had pulmonary interstitial glycogenosis, which contributed to significant morbidity. There was striking clinical improvement after steroid treatment of the pulmonary interstitial glycogenosis.Conclusions: Interstitial lung disease should be considered as a differential diagnosis when respiratory distress and hypoxemia in the perinatal period worsens or persists despite standard treatment. Importantly, pulmonary interstitial glycogenosis may be treatable with corticosteroids. Whether there is a genetic link between pulmonary interstitial glycogenosis and Jacobsen syndrome is still unknown. [ABSTRACT FROM AUTHOR]

Purpose: Jacobsen syndrome (JS) is a rare form of genetic disorder that was recently classified as a syndromic immunodeficiency. Available detailed immunological data from JS patients are limited. Methods: Clinical and immunological presentation of twelve pediatric patients with JS by means of revision of clinical records, flow cytometry, real-time PCR, and lymphocyte functional testing were collected. Results: Recurrent infections were registered in 6/12 patients (50%), while bleeding episodes in 2/12 (16.7%). White blood cell and absolute lymphocyte counts were reduced in 8/12 (66.7%) and 7/12 (58.3%) patients, respectively. Absolute numbers of CD3+ and CD4+ T cells were reduced in 8/12 (66.7%) and 7/12 (58.3%), respectively. Of note, recent thymic emigrants (RTE) were reduced in all tested patients (9/9), with T-cell receptor excision circle analysis (TRECs) showing a similar trend in 8/9 patients; naïve CD4+ T cells were low only in 5/11 patients (45.4%). Interestingly, B-cell counts, IgM memory B cells, and IgM serum levels were reduced in 10/12 (83.3%) patients. Natural killer (NK) cell counts were mostly normal but the percentages of CD16+CD56low/− cells were expanded in 7/7 patients tested. The observed immunological alterations did not correlate with patients' age. Finally, responses to proliferative stimuli were normal at presentation for all patients, although they may deteriorate over time. Conclusions: Our data suggest that patients affected with JS may display important numeric and maturational alterations in the T-, B-, and NK-cell compartments. These findings suggest that JS patients should be regularly monitored from an immunological point of view. [ABSTRACT FROM AUTHOR]

Jacobsen syndrome (JS) is a rare syndrome caused by a deletion of chromosome 11q. We report a patient with JS and hypoplastic left heart syndrome (HLHS) who required cardiac transplantation. She had many of the recognized morphological features in addition to immunological (lymphopenia) and hematological (thrombocytopenia) issues. The patient underwent a Norwood procedure with a modified Blalock–Taussig shunt (MBTS) and subsequently a Glenn procedure at six months of age. She developed desaturation, with severe tricuspid regurgitation and right ventricular dysfunction, and underwent heart transplantation at 7 months of age. After the transplant, she was hospitalized several times for severe infections. The diagnosis of Jacobsen syndrome came 2 months after transplant. Now, 5 years post-transplant, she is in relatively good health—her heart is functioning normally, her hospitalization rate is getting lower, and her immunological profile is stable.

We have identified the ETS1 gene as the cause of congenital heart defects, including an unprecedented high frequency of HLHS, in the chromosomal disorder Jacobsen syndrome. Studies in Ciona intestinalis demonstrated a critical role for ETS1 in heart cell fate determination and cell migration, suggesting that the impairment of one or both processes can underlie the pathogenesis of HLHS. Our studies determined that ETS1 is expressed in the cardiac neural crest and endocardium in the developing murine heart, implicating one or both lineages in the development of HLHS. Studies in Drosophila and Xenopus demonstrated a critical role for ETS1 in regulating cardiac cell fate determination, and results in Xenopus provided further evidence for the role of the endocardium in the evolution of the “hypoplastic” HLHS LV. Paradoxically, these studies suggest that the loss of ETS1 may cause a cell fate switch resulting in the loss of endocardial cells and a relative abundance of cardiac myocytes. These studies implicate an “HLHS transcriptional network” of genes conserved across species that are essential for early heart development. Finally, the evidence suggests that in a subset of HLHS patients, the HLHS LV cardiac myocytes are, intrinsically, developmentally and functionally normal, which has important implications for potential future therapies.

Pediatric hypoparathyroidism (HPT) is caused by inherited or acquired defects involving the synthesis or secretion of PTH, resistance to PTH action, or inappropriate regulation of PTH. Several syndromes such as DiGeorge syndrome, HDR (hypoparathyroidism, sensorineural deafness and renal dysplasia) syndrome, HRD (hypoparathyroidism, retardation, and dysmorphism) syndrome, Kenny-Caffey syndrome etc. may have associated HPT. In the present communication, we describe, the hitherto unreported, occurrence of HPT in a child with partial Jacobsen syndrome. Chromosomal Microarray analysis showed a heterozygous deletion of 4.7 Mb at cytoband 11q24.3q25 encompassing approximately 20 genes including JAM3 and NTM genes. The child was treated with recombinant human parathyroid hormone (rhPTH1-34) for 10 years. Throughout follow up, he required several adjustments in dosages of rhPTH1-34 and oral calcium to maintain serum calcium concentrations in low normal ranges. The bone turnover markers remained normal and oral calcium supplements were completely taken off after 8 years. In conclusion, our single-case experience indicates that long-term therapy of chronic HPT with rhPTH1-34 is safe and reduces the need for additional therapies. [ABSTRACT FROM AUTHOR]

Abstract Background 11q23 deletion syndrome, also known as Jacobsen syndrome, is characterized by growth retardation, psychomotor retardation, facial dysmorphism, multiple congenital abnormalities, and thrombocytopenia. In 11q23 deletion syndrome, it is often difficult to anticipate the severity of bleeding. We report a neonatal case of 11q23 deletion syndrome with bleeding that was more severe than predicted by the platelet count. Case presentation We report a case of 11q23 deletion syndrome in an Asian male newborn with severe bleeding just after birth. The diagnosis of 11q23 deletion syndrome was made prenatally by amniocentesis. An array comparative genomic hybridization analysis revealed a deletion of the 13.0 Mb regions ranging from 11q24.1 to the q terminus encoding FLI1. Our patient was delivered by cesarean section and exhibited skull deformities, facial asymmetry, low-set ears, inguinal hernia, flat feet, and crowded toes. He had a low platelet count (45,000/μL) and a coagulation abnormality with a prothrombin time–international normalized ratio of 1.92 and an activated partial thromboplastin time of 158.6 seconds. Bleeding at the site of a peripheral vessel puncture was more severe than expected with thrombocytopenia. The peripheral blood featured two different sizes of platelets containing large α-granules. As a result, he required eight platelet transfusions and two fresh frozen plasma transfusions within 13 days of birth. Massive bleeding was avoided, and cerebral magnetic resonance imaging indicated the occurrence of only petechial hemorrhage. Conclusions Our patient with 11q deletion including FLI1 avoided massive bleeding and serious sequelae because of careful management after prenatal diagnosis. We suggest that prenatal diagnosis and vigilant perinatal care including a cesarean section are warranted for patients with 11q23 deletion syndrome.

Jacobsen syndrome (JS) is caused by a deletion at the terminus of the long arm of chromosome 11. There are few reports of JS associated with cerebral white matter abnormalities (WMA), and the etiology, pathophysiology, and time-dependent changes in WMA with JS still remain unclear. The patient was a 2-month-old female with several morphological anomalies, including trigonocephaly, ectropion, flat nasal bridge, low-set ears, and sparse eyebrows. Chromosome analysis (G-banding karyotyping) of 46,XX,del(11)(q23.3) led to the diagnosis of JS. Head MRI performed at age 9 months indicated diffuse WMA with hyperintense signals on T2-weighted imaging. MRI at age 2.5 years demonstrated a decrease in the WMA and progressive myelination. These findings suggested that the WMA in the present patient were due to chronic white matter edema associated with a deletion in the 11q terminal region of HEPACAM / GlialCAM , a causative gene for megalencephalic leukoencephalopathy with subcortical cysts type 2B (MLC2B). As with some of MLC2B patients, the WMA in the present patient improved over time. The present report is the first to document dramatic changes in WMA in JS visualized by serial MRI examinations from the neonatal period through early childhood. The findings of the present study suggested that WMA in JS are due to chronic white matter edema associated with HEPACAM / GlialCAM deletion and show gradual improvement over time, as seen in some MLC2B patients. [ABSTRACT FROM AUTHOR]

Objective: We present molecular cytogenetic characterization of Jacobsen syndrome (11q23.3-q25 deletion) in a fetus associated with double outlet right ventricle (DORV), hypoplastic left heart syndrome (HLHS), and ductus venosus (DV) agenesis on prenatal ultrasound. Case Report: A 26-year-old woman underwent prenatal ultrasound examination at 22 weeks of gestation, which revealed intrauterine growth restriction, short femurs, DORV, HLHS, DV agenesis, single umbilical artery, and curly fourth toe of the left foot. The parents elected to terminate the pregnancy, and a 500-g female fetus was delivered at 23 weeks of gestation with facial dysmorphism, bilateral camptodactyly, and hammertoes. The parental karyotypes were normal. Cytogenetic analysis of the cord blood and umbilical cord revealed a karyotype of 46,XX,del(11)(q23). Array comparative genomic hybridization analysis of the DNA extracted from the umbilical cord revealed a 14.38-Mb deletion of 11q23.3-q25 encompassing BSX, ETS1, FLI1, and ARHGAP32. Metaphase fluorescence in situ hybridization analysis using the probes RP11-209L12 (11q25) and RP11-25M7 (11q11) showed a distal 11q deletion in the aberrant chromosome 11 in 17/17 cells examined. Conclusion: Prenatal diagnosis of DORV, HLHS, DV agenesis associated with intrauterine growth restriction and short limbs should include a differential diagnosis of Jacobsen syndrome.

This report presents two families with interstitial 11q24.2q24.3 deletion, associated with malformations, hematologic features, and typical facial dysmorphism, observed in Jacobsen syndrome (JS), except for intellectual disability (ID). The smallest 700 Kb deletion contains only two genes: FLI1 and ETS1, and a long noncoding RNA, SENCR, narrowing the minimal critical region for some features of JS. Consistent with recent literature, it adds supplemental data to confirm the crucial role of FLI1 and ETS1 in JS, namely FLI1 in thrombocytopenia and ETS1 in cardiopathy and immune deficiency. It also supports that combined ETS1 and FLI1 haploinsufficiency explains dysmorphic features, notably ears, and nose anomalies. Moreover, it raises the possibility that SENCR, a long noncoding RNA, could be responsible for limb defects, because of its early role in endothelial cell commitment and function. Considering ID and autism spectrum disorder, which are some of the main features of JS, a participation of ETS1, FLI1, or SENCR cannot be excluded. But, considering the normal neurodevelopment of our patients, their role would be either minor or with an important variability in penetrance. Furthermore, according to literature, ARHGAP32 and KIRREL3 seem to be the strongest candidate genes in the 11q24 region for other Jacobsen patients. [ABSTRACT FROM AUTHOR]

Abstract Jacobsen syndrome refers to a congenital anomaly caused by deletion at 11q23.3-qter. We here describe two siblings with the same 11q23.3-qter deletion. Both parents were healthy with a normal karyotype. Cytogenetic microarray analysis revealed no mosaicism in either parent but the mother showed uniparental disomy encompassing the deleted region found in the two siblings. The pattern of X chromosome inactivation was almost completely skewed in the mother. These data suggested that the mother was a carrier of the 11q23.3-qter deletion but that this had been rescued by disomy formation during early embryogenesis except for her germinal cells. [ABSTRACT FROM AUTHOR]

Ets‐1 is a member of the Ets family of transcription factors and has critical roles in multiple biological functions. Structural kidney defects occur at an increased frequency in Jacobsen syndrome (OMIM #147791), a rare chromosomal disorder caused by deletions in distal 11q, implicating at least one causal gene in distal 11q. In this study, we define an 8.1 Mb "critical region" for kidney defects in Jacobsen syndrome, which spans ~50 genes. We demonstrate that gene‐targeted deletion of Ets‐1 in mice results in some of the most common congenital kidney defects occurring in Jacobsen syndrome, including: duplicated kidney, hypoplastic kidney, and dilated renal pelvis and calyces. Taken together, our results implicate Ets‐1 in normal mammalian kidney development and, potentially, in the pathogenesis of some of the most common types of human structural kidney defects. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Jacobsen syndrome (JS) is a rare contiguous gene disorder caused by partial deletion of the distal part of the long arm of chromosome 11 ranging in size from 7 to 20 Mb. We report a term male neonate with an interstitial deletion of about 12.3 megabase (Mb) of chromosome 11q24.1qter. Our case is the first reported newborn patient with 11q24 deletion. [ABSTRACT FROM AUTHOR]

Background: 11q23 deletion syndrome, also known as Jacobsen syndrome, is characterized by growth retardation, psychomotor retardation, facial dysmorphism, multiple congenital abnormalities, and thrombocytopenia. In 11q23 deletion syndrome, it is often difficult to anticipate the severity of bleeding. We report a neonatal case of 11q23 deletion syndrome with bleeding that was more severe than predicted by the platelet count.Case Presentation: We report a case of 11q23 deletion syndrome in an Asian male newborn with severe bleeding just after birth. The diagnosis of 11q23 deletion syndrome was made prenatally by amniocentesis. An array comparative genomic hybridization analysis revealed a deletion of the 13.0 Mb regions ranging from 11q24.1 to the q terminus encoding FLI1. Our patient was delivered by cesarean section and exhibited skull deformities, facial asymmetry, low-set ears, inguinal hernia, flat feet, and crowded toes. He had a low platelet count (45,000/μL) and a coagulation abnormality with a prothrombin time-international normalized ratio of 1.92 and an activated partial thromboplastin time of 158.6 seconds. Bleeding at the site of a peripheral vessel puncture was more severe than expected with thrombocytopenia. The peripheral blood featured two different sizes of platelets containing large α-granules. As a result, he required eight platelet transfusions and two fresh frozen plasma transfusions within 13 days of birth. Massive bleeding was avoided, and cerebral magnetic resonance imaging indicated the occurrence of only petechial hemorrhage.Conclusions: Our patient with 11q deletion including FLI1 avoided massive bleeding and serious sequelae because of careful management after prenatal diagnosis. We suggest that prenatal diagnosis and vigilant perinatal care including a cesarean section are warranted for patients with 11q23 deletion syndrome. [ABSTRACT FROM AUTHOR]

Hypoplastic left heart syndrome occurs in up to 3% of all infants born with congenital heart disease and is a leading cause of death in this population. Although there is strong evidence for a genetic component, a specific genetic cause is only known in a small subset of patients, consistent with a multifactorial etiology for the syndrome. There is controversy surrounding the mechanisms underlying the syndrome, which is likely due, in part, to the phenotypic variability of the disease. The most commonly held view is that the “decreased„ growth of the left ventricle is due to a decreased flow during a critical period of ventricular development. Research has also been hindered by what has been, up until now, a lack of genetically engineered animal models that faithfully reproduce the human disease. There is a growing body of evidence, nonetheless, indicating that the hypoplasia of the left ventricle is due to a primary defect in ventricular development. In this review, we discuss the evidence demonstrating that, at least for a subset of cases, the chamber hypoplasia is the consequence of hyperplasia of the contained cardiomyocytes. In this regard, hypoplastic left heart syndrome could be viewed as a neonatal form of cardiomyopathy. We also discuss the role of the endocardium in the development of the ventricular hypoplasia, which may provide a mechanistic basis for how impaired flow to the developing ventricle leads to the anatomical changes seen in the syndrome.

Jacobsen syndrome is a rare chromosomal disorder caused by distal deletions in the long arm of chromosome 11. All patients with Jacobsen syndrome have Paris-Trousseau syndrome, a bleeding disorder that causes neonatal thrombocytopenia, and persistent platelet dysfunction. Despite that, to date there are no reported cases of hemorrhagic strokes occurring in patients with Jacobsen syndrome. In the last 6 years at least six cases of brain hemorrhages in patients with Jacobsen syndrome have occurred. In this report, we perform a retrospective review of these six cases. The analysis indicates that the etiology of brain hemorrhages in Jacobsen syndrome is likely multifactorial. A likely cause (or causes) was identified in three of the cases, and additional potential risk factors were identified. Based on these findings, clinical recommendations are provided that should aid in the identification of those individuals with Jacobsen syndrome that are at increased risk for brain hemorrhages, and will hopefully decrease the occurrence of this devastating complication in people with Jacobsen syndrome.© 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Antibody deficiency is common finding in patients with Jacobsen syndrome (JS). In addition, there have been few reports of T-cell defects in this condition, possibly because most of the reported patients have not been specifically evaluated for T-cell function. In this article, we present a child with an 11q deletion and combined immunodeficiency and we perform a literature overview on immunodeficiency in JS. Our patient presented with recurrent bacterial and prolonged viral infections involving the respiratory system, as well as other classic features of the syndrome. In addition to low IgM, IgG4, and B-cells, also low recent thymic emigrants, helper and naïve T-cells were found. We propose that patients with Jacobsen syndrome need thorough immunological evaluations as T-cell dysfunction might be more prevalent than previously reported. Patients with infections consistent with T-cell defects should be classified as having combined immunodeficiency. [ABSTRACT FROM AUTHOR]