UNASSIGNED:
UNASSIGNED: Inherited thrombocytopenias (ITs) are rare congenital bleeding disorders characterized by different clinical expression and variable prognosis. ITs are poorly known by clinicians and often misdiagnosed with most common forms of thrombocytopenia.
UNASSIGNED: \"CHildren with Inherited Platelet disorders Surveillance\" study (CHIPS) is a retrospective - prospective observational cohort study conducted between January 2003 and January 2022 in 17 centers affiliated to the Italian Association of Pediatric Hematology and Oncology (AIEOP). The primary objective of this study was to collect clinical and laboratory data on Italian pediatric patients with inherited thrombocytopenias. Secondary objectives were to calculate prevalence of ITs in Italian pediatric population and to assess frequency and genotype-phenotype correlation of different types of mutations in our study cohort.
UNASSIGNED: A total of 139 children, with ITs (82 male - 57 female) were enrolled. ITs prevalence in Italy ranged from 0.7 per 100,000 children during 2010 to 2 per 100,000 children during 2022. The median time between the onset of thrombocytopenia and the diagnosis of ITs was 1 years (range 0 - 18 years). A family history of thrombocytopenia has been reported in 90 patients (65%). Among 139 children with ITs, in 73 (53%) children almost one defective gene has been identified. In 61 patients a pathogenic mutation has been identified. Among them, 2 patients also carry a variant of uncertain significance (VUS), and 4 others harbour 2 VUS variants. VUS variants were identified in further 8 patients (6%), 4 of which carry more than one variant VUS. Three patients (2%) had a likely pathogenic variant while in 1 patient (1%) a variant was identified that was initially given an uncertain significance but was later classified as benign. In addition, in 17 patients the genetic diagnosis is not available, but their family history and clinical/laboratory features strongly suggest the presence of a specific genetic cause. In 49 children (35%) no genetic defect were identified. In ninetyseven patients (70%), thrombocytopenia was not associated with other clinically apparent disorders. However, 42 children (30%) had one or more additional clinical alterations.
UNASSIGNED: Our study provides a descriptive collection of ITs in the pediatric Italian population.

Noonan syndrome (NS) is a genetic disorder with distinctive physical features and often multiple organ involvement. Bleeding disorders are reported in over half of patients with NS, including thrombocytopenia and platelet dysfunction. Neonatal alloimmune thrombocytopenia (NAIT) is an alloantigenic thrombocytopenia that can present with severe bleeding. Here, we present a case of intracranial hemorrhage and severe thrombocytopenia in a neonate found to have both NAIT and a de novo heterozygous pathogenic variant in PTPN11, consistent with Noonan syndrome.

May-Hegglin anomaly (MHA) is a rare autosomal dominant disorder in the spectrum of myosin heavy chain-related disorders (MYH9-RD), characterized by congenital macrothrombocytopenia and white blood cell inclusions. MHA carries a potential risk of hemorrhagic complications. Bleeding diathesis is usually mild, but sporadic, life-threatening events have been reported. Data regarding the clinical course and outcomes of neonatal MYH9-RD are limited, and specific guidelines on platelet transfusion in asymptomatic patients are lacking. We present monochorionic twins born preterm at 32 weeks of gestation to an MHA mother; both presented with severe thrombocytopenia at birth. Peripheral blood smear demonstrated the presence of macrothrombocytes, and immunofluorescence confirmed the diagnosis of MHA. Close clinical monitoring excluded bleeding complications, and serial hemostatic assessments through a viscoelastic system demonstrated functionally normal primary hemostasis in both patients. Therefore, prophylactic platelet transfusions were avoided. Whole DNA sequencing confirmed the pathogenetic variant of MHA of maternal origin in both twins. Thromboelastography allowed real-time bedside bleeding risk assessment and supported individualized transfusion management in preterm newborns at risk of hemostatic impairment. This report suggests that dynamic and appropriate clotting monitoring may contribute to the more rational use of platelets\' transfusions while preserving patients with hemorrhagic complications and potential transfusion-related side effects.

Congenital thrombocytopenia is a group of heterogeneous disorders caused by mutations in the responsible genes that play crucial roles in normal megakaryopoiesis and subsequent platelet production. The diagnosis of congenital thrombocytopenia is clinically necessary to distinguish it from immune thrombocytopenia and select the appropriate therapeutic modalities. The number of responsible genes reported so far is up to 56, and data on their targeted sequencing and subsequent exome sequencing analysis are available in Japan. Here, we report the disease outlines, disease classification based on platelet sizes (small, normal, large, and giant platelets), disease descriptions, consultation system, list of responsible genes, therapeutic options, and follow-up system for congenital thrombocytopenia.

Neonatal thrombocytopenia is common in preterm and term neonates admitted to neonatal intensive care units. The etiology behind neonatal thrombocytopenia is complex. Inherited thrombocytopenia is rare and usually results from genetic mutations.
Here we report a case of twins with severe inherited thrombocytopenia presented in the neonatal period who were shown to be compound heterozygotes for 2 UDP-N-acetylglucosamine 2-epimerase (GNE) gene mutations, c.1351C > T and c.1330G > T, of which c.1330G > T is a novel mutation.
These two GNE mutations may help in the diagnosis and management of thrombocytopenia diagnosed in neonates.

暂无摘要。

Thrombocytopenia-absent radii (TAR) syndrome, characterized by neonatal thrombocytopenia and bilateral radial aplasia with thumbs present, is typically caused by the inheritance of a 1q21.1 deletion and a single-nucelotide polymorphism in RBM8A on the nondeleted allele. We evaluated two siblings with TAR-like dysmorphology but lacking thrombocytopenia in infancy. Family NCI-107 participated in an IRB-approved cohort study and underwent comprehensive clinical and genomic evaluations, including aCGH, whole-exome, whole-genome, and targeted sequencing. Gene expression assays and electromobility shift assays (EMSAs) were performed to evaluate the variant of interest. The previously identified TAR-associated 1q21.1 deletion was present in the affected siblings and one healthy parent. Multiple sequencing approaches did not identify previously described TAR-associated SNPs or mutations in relevant genes. We discovered rs61746197 A > G heterozygosity in the parent without the deletion and apparent hemizygosity in both siblings. rs61746197 A > G overlaps a RelA-p65 binding motif, and EMSAs indicate the A allele has higher transcription factor binding efficiency than the G allele. Stimulation of K562 cells to induce megakaryocyte differentiation abrogated the shift of both reference and alternative probes. The 1q21.1 TAR-associated deletion in combination with the G variant of rs61746197 on the nondeleted allele is associated with a TAR-like phenotype. rs61746197 G could be a functional enhancer/repressor element, but more studies are required to identify the specific factor(s) responsible. Overall, our findings suggest a role of rs61746197 A > G and human disease in the setting of a 1q21.1 deletion on the other chromosome.

Congenital thrombocytopenias are a genetically and clinically heterogeneous group of platelet disorders that are characterized by thrombocytopenia since birth. Although very rare, these disorders are encountered in routine clinical practice. Since 2011, the application of next generation sequencing has identified more than 15 new genes, which, when mutated, can cause congenital thrombocytopenia. Currently, at least 35 different forms have been identified. Although thrombocytopenia is congenital, some forms present an elevated risk of developing additional complications. In MYH9 disorders, patients often develop nephritis, deafness, and cataract. In a subgroup of congenital thrombocytopenias, with defects in the TPO/MPL signaling pathways or transcription factors, enhanced or reduced hematopoietic cell proliferation properties often culminates in the development of hematological malignancy or bone marrow failure. Proper and early genetic diagnosis is essential for the treatment of congenital thrombocytopenia.

Recent evidence has implicated EFL1 in a phenotype overlapping Shwachman-Diamond syndrome (SDS), with the functional interplay between EFL1 and the previously known causative gene SBDS accounting for the similarity in clinical features. Relatively little is known about the phenotypes associated with pathogenic variants in the EFL1 gene, but the initial indication was that phenotypes may be more severe, when compared with SDS. We report a pediatric patient who presented with a metaphyseal dysplasia and was found to have biallelic variants in EFL1 on reanalysis of trio whole-exome sequencing data. The variant had not been initially reported because of the research laboratory\'s focus on de novo variants. Subsequent phenotyping revealed variability in her manifestations. Although her metaphyseal abnormalities were more severe than in the original reported cohort with EFL1 variants, the bone marrow abnormalities were generally mild, and there was equivocal evidence for pancreatic insufficiency. Despite the limited number of reported patients, variants in EFL1 appear to cause a broader spectrum of symptoms that overlap with those seen in SDS. Our report adds to the evidence of EFL1 being associated with an SDS-like phenotype and provides information adding to our understanding of the phenotypic variability of this disorder. Our report also highlights the value of exome data reanalysis when a diagnosis is not initially apparent.

Interstitial deletions encompassing the 3q26.2 region are rare. Only one case-report was published this far describing a patient with an interstitial deletion of 3q26.2 (involving the MDS1-EVI1 complex (MECOM)) and congenital thrombocytopenia. In this report we describe a case of a neonate with congenital thrombocytopenia and a constitutional 4.52 Mb deletion of 3q26.2q26.31 including TERC and the first 2 exons of MECOM, involving MDS1 but not EVI1. The deletion was demonstrated by array-CGH on lymphocytes. Our report confirms that congenital thrombocytopenia can be due to a constitutional deletion of 3q26.2 involving MECOM. We suggest that in case of unexplained neonatal thrombocytopenia, with even just slight facial dysmorphism, DNA microarray on peripheral blood should be considered early in the diagnostic work-up.