Novel F8 and F9 gene variants from the PedNet hemophilia registry classified according to ACMG/AMP guidelines

In hemophilia A and B, analysis of theF8andF9gene variants enables carrier and prenatal diagnosis and prediction of risk for the development of inhibitors. The PedNet Registry collects clinical, genetic, and phenotypic data prospectively on more than 2000 children with hemophilia. The genetic reports ofF8/F9gene variants were classified uniformly to Human Genome Variation Society nomenclature and reevaluated using international population- and disease-specific databases, literature survey and, where applicable, computational predictive programs. We report 88 novel variants in theF8andF9genes, 80 fulfilling criteria for Class 5 (pathogenic), six for Class 4 (likely pathogenic) and two fulfilling criteria for Class 3 (variant of unknown significance) of the American College of Medical Genetics and Genomics/Association for Molecular Pathologyguidelines together with information on the respective phenotype and inhibitor formation. The study highlights the need to reevaluate and update earlier genetic reports in hemophilia both locally but also in variant databases in light of changed nomenclature and new guidelines.Peer reviewe

Subconjunctival Hemorrhage in a Child with the Blue Rubber Bleb Nevus Syndrome on Treatment with Oral Propranolol

Blue rubber bleb nevus syndrome (BRBNS) is a rare syndrome characterized by venous malformations of mostly skin and gastrointestinal tract. Patients present with multiple venous malformations in various organs including liver, spleen, heart, eye, and central nervous system. Few ophthalmological cases have been published in literature and at present, there are no clear guidelines on the treatment of eye hemorrhages associated with the BRBNS. We report a 3-year-old boy with the BRBNS who developed a spontaneous progressive enlarging subconjunctival hemorrhage in the left eye despite being treated with oral propranolol. The subconjunctival hemorrhage was caused by an underlying conjunctival vascular malformation. With topical treatment with timolol maleate 0.5% once a day in the affected eye, the lesion regressed completely after 4 months. This child represents the first case of the BRBNS associated with a subconjunctival progressive bleeding necessitating topical treatment despite oral propranolol effectively controlling the cutaneous lesions. We recommend ophthalmic screening of patients with BRBNS in early childhood. For patients with BRBNS-related subconjunctival vascular lesions with subsequent hemorrhage, treatment with a topical β-blocker may be an efficient and harmless treatment option

What’s new in using platelet research? To unravel thrombopathies and other human disorders

This review on platelet research focuses on defects of adhesion, cytoskeletal organisation, signal transduction and secretion. Platelet defects can be studied by different laboratory platelet functional assays and morphological studies. Easy bruising or a suspected platelet-based bleeding disorder is of course the most obvious reason to test the platelet function in a patient. However, nowadays platelet research also contributes to our understanding of human pathology in other disciplines such as neurology, nephrology, endocrinology and metabolic diseases. Apart from a discussion on classical thrombopathies, this review will also deal with the less commonly known relation between platelet research and disorders with a broader clinical phenotype. Classical thrombopathies involve disorders of platelet adhesion such as Glanzmann thrombastenia and Bernard-Soulier syndrome, defective G protein signalling diseases with impaired phospholipase C activation, and abnormal platelet granule secretion disorders such as gray platelet disorder and delta-storage pool disease. Other clinical symptoms besides a bleeding tendency have been described in MYH9-related disorders and Duchenne muscular dystrophy due to adhesion defects, and also in disorders of impaired Gs signalling, in Hermansky Pudlack disease and Chediak Higashi disease with abnormal secretion. Finally, platelet research can also be used to unravel novel mechanisms involved in many neurological disorders such as depression and autism with only a subclinical platelet defect

Case report: Cardiac intimal sarcoma in a young child

Undifferentiated mesenchymal tumors from the intimal layer (intimal sarcomas) are rare within the ventricles and exceptional in children. A rare case of an intimal sarcoma located in the right ventricle in a young child is presented with need for urgent surgical resection due to mechanical flow obstruction. Tumor cells showed amplification of MDM2 gene and a homozygous loss of CDKN2A on 9p21. A review of the literature regarding primary cardiac malignancies and intimal sarcoma in children is provided

Sphingolipid dysregulation due to lack of functional KDSR impairs proplatelet formation causing thrombocytopenia.

Sphingolipids are fundamental to membrane trafficking, apoptosis, and cell differentiation and proliferation. KDSR or 3-keto-dihydrosphingosine reductase is an essential enzyme for de novo sphingolipid synthesis, and pathogenic mutations in KDSR result in the severe skin disorder erythrokeratodermia variabilis et progressiva-4 Four of the eight reported cases also had thrombocytopenia but the underlying mechanism has remained unexplored. Here we expand upon the phenotypic spectrum of KDSR deficiency with studies in two siblings with novel compound heterozygous variants associated with thrombocytopenia, anemia, and minimal skin involvement. We report a novel phenotype of progressive juvenile myelofibrosis in the propositus, with spontaneous recovery of anemia and thrombocytopenia in the first decade of life. Examination of bone marrow biopsies showed megakaryocyte hyperproliferation and dysplasia. Megakaryocytes obtained by culture of CD34+ stem cells confirmed hyperproliferation and showed reduced proplatelet formation. The effect of KDSR insufficiency on the sphingolipid profile was unknown, and was explored in vivo and in vitro by a broad metabolomics screen that indicated activation of an in vivo compensatory pathway that leads to normalization of downstream metabolites such as ceramide. Differentiation of propositus-derived induced pluripotent stem cells to megakaryocytes followed by expression of functional KDSR showed correction of the aberrant cellular and biochemical phenotypes, corroborating the critical role of KDSR in proplatelet formation. Finally, Kdsr depletion in zebrafish recapitulated the thrombocytopenia and showed biochemical changes similar to those observed in the affected siblings. These studies support an important role for sphingolipids as regulators of cytoskeletal organization during megakaryopoiesis and proplatelet formation

LIN28B overexpression defines a novel fetal-like subgroup of juvenile myelomonocytic leukemia

Juvenile myelomonocytic leukemia (JMML) is a rare and aggressive stem cell disease of early childhood. RAS activation constitutes the core component of oncogenic signaling. In addition, leukemic blasts in one-fourth of JMML patients present with monosomy 7, and more than half of patients show elevated age-adjusted fetal hemoglobin (HbF) levels. Hematopoietic stem cell transplantation is the current standard of care and results in an event-free survival rate of 50% to 60%, indicating that novel molecular-driven therapeutic options are urgently needed. Using gene expression profiling in a series of 82 patient samples, we aimed at understanding the molecular biology behind JMML and identified a previously unrecognized molecular subgroup characterized by high LIN28B expression. LIN28B over expression was significantly correlated with higher HbF levels, whereas patients with monosomy 7 seldom showed enhanced LIN28B expression. This finding gives a biological explanation of why patients with monosomy7 are rarely diagnosed with high age-adjusted HbF levels. In addition, this new fetal-like JMML subgroup presented with reduced levels of most members of the let-7 microRNA family and showed characteristic overexpression of genes involved in fetal hematopoiesis and stem cell self-renewal. Lastly, high LIN28B expression was associated with poor clinical outcome in our JMML patient series but was not independent from other prognostic factors such as age and age-adjusted HbF levels. In conclusion, we identified elevated LIN28B expression as a hallmark of a novel fetal-like subgroup in JMM

Methylation Defect in Imprinted Genes Detected in Patients with an Albright's Hereditary Osteodystrophy Like Phenotype and Platelet Gs Hypofunction

Pseudohypoparathyroidism (PHP) indicates a group of heterogeneous disorders whose common feature is represented by impaired signaling of hormones that activate Gsalpha, encoded by the imprinted GNAS gene. PHP-Ib patients have isolated Parathormone (PTH) resistance and GNAS epigenetic defects while PHP-Ia cases present with hormone resistance and characteristic features jointly termed as Albright's Hereditary Osteodystrophy (AHO) due to maternally inherited GNAS mutations or similar epigenetic defects as found for PHP-Ib. Pseudopseudohypoparathyroidism (PPHP) patients with an AHO phenotype and no hormone resistance and progressive osseous heteroplasia (POH) cases have inactivating paternally inherited GNAS mutations.We here describe 17 subjects with an AHO-like phenotype that could be compatible with having PPHP but none of them carried Gsalpha mutations. Functional platelet studies however showed an obvious Gs hypofunction in the 13 patients that were available for testing. Methylation for the three differentially methylated GNAS regions was quantified via the Sequenom EpiTYPER. Patients showed significant hypermethylation of the XL amplicon compared to controls (36 ± 3 vs. 29 ± 3%; p<0.001); a pattern that is reversed to XL hypomethylation found in PHPIb. Interestingly, XL hypermethylation was associated with reduced XLalphaS protein levels in the patients' platelets. Methylation for NESP and ExonA/B was significantly different for some but not all patients, though most patients have site-specific CpG methylation abnormalities in these amplicons. Since some AHO features are present in other imprinting disorders, the methylation of IGF2, H19, SNURF and GRB10 was quantified. Surprisingly, significant IGF2 hypermethylation (20 ± 10 vs. 14 ± 7%; p<0.05) and SNURF hypomethylation (23 ± 6 vs. 32 6%; p<0.001) was found in patients vs. controls, while H19 and GRB10 methylation was normal.In conclusion, this is the first report of methylation defects including GNAS in patients with an AHO-like phenotype without endocrinological abnormalities. Additional studies are still needed to correlate the methylation defect with the clinical phenotype

Highlights in red blood cell disorders

status: publishe

Chinese and Belgian pediatricians’ perspectives toward pediatric palliative care: an online survey

Background As pediatricians play a vital role in pediatric palliative care (PPC), understanding their perspectives toward PPC is important. PPC is established for a long time in Belgium, but has a shorter tradition in China, although it is growing in the last decade. Sampling and comparing the perspectives of these pediatricians could be insightful for both countries. Therefore, we sampled and compared perspectives of pediatricians in China and Belgium toward PPC, and explored factors influencing their perspectives. Methods We conducted a cross-sectional online survey using the validated Pediatric Palliative Care Attitude Scale (PPCAS). Over a five-month period, we recruited pediatricians practicing in China (C) and Flanders (F), Belgium. Convenience sampling and snowballing were used. We analyzed data with descriptive statistics, and evaluated group differences with univariate, multivariate and correlation tests. Results 440 complete surveys were analyzed (F: 115; C: 325). Pediatricians in both regions had limited PPC experience (F: 2.92 ± 0.94; C: 2.76 ± 0.92). Compared to Flemish pediatricians, Chinese pediatricians perceived receiving less unit support (F: 3.42 ± 0.86; C: 2.80 ± 0.89); perceived PPC less important (F: 4.70 ± 0.79; C: 4.18 ± 0.94); and faced more personal obstacles while practicing PPC (F: 3.50 ± 0.76; C: 2.25 ± 0.58). Also, select socio-demographic characteristics (e.g., experiences caring for children with life-threatening condition and providing PPC) influenced pediatricians’ perspectives. Correlational analyses revealed that pediatricians’ PPC experiences significantly correlated with perceived unit support (ρ$_{F}$ = 0.454; ρ$_{C=}$0.661). Conclusions Chinese pediatricians faced more barriers in practicing PPC. Expanding PPC experiences can influence pediatricians’ perspectives positively, which may be beneficial for the child and their family

Physicians’ attitudes and experiences about withholding/withdrawing life-sustaining treatments in pediatrics: a systematic review of quantitative evidence

Abstract Background One of the most important and ethically challenging decisions made for children with life-limiting conditions is withholding/withdrawing life-sustaining treatments (LST). As important (co-)decision-makers in this process, physicians are expected to have deeply and broadly developed views. However, their attitudes and experiences in this area remain difficult to understand because of the diversity of the studies. Hence, the aim of this paper is to describe physicians’ attitudes and experiences about withholding/withdrawing LST in pediatrics and to identify the influencing factors. Methods We systematically searched Pubmed, Cinahl®, Embase®, Scopus®, and Web of Science™ in early 2021 and updated the search results in late 2021. Eligible articles were published in English, reported on investigations of physicians’ attitudes and experiences about withholding/withdrawing LST for children, and were quantitative. Results In 23 included articles, overall, physicians stated that withholding/withdrawing LST can be ethically legitimate for children with life-limiting conditions. Physicians tended to follow parents’ and parents-patient’s wishes about withholding/withdrawing or continuing LST when they specified treatment preferences. Although most physicians agreed to share decision-making with parents and/or children, they nonetheless reported experiencing both negative and positive feelings during the decision-making process. Moderating factors were identified, including barriers to and facilitators of withholding/withdrawing LST. In general, there was only a limited number of quantitative studies to support the hypothesis that some factors can influence physicians’ attitudes and experiences toward LST. Conclusion Overall, physicians agreed to withhold/withdraw LST in dying patients, followed parent-patients’ wishes, and involved them in decision-making. Barriers and facilitators relevant to the decision-making regarding withholding/withdrawing LST were identified. Future studies should explore children’s involvement in decision-making and consider barriers that hinder implementation of decisions about withholding/withdrawing LST