Single-center clinical analysis of hereditary thrombocytopenia in children with chronic thrombocytopenia

Objective To know the detection rate of hereditary thrombocytopenia (HT) in children with chronic thrombocytopenia and its clinical and laboratory characteristics for an early clinical identification and diagnosis of HT in future. Methods Data of the children with thrombocytopenia, who had been treated in Beijing Children′s Hospital from April 2016 to May 2018 and whose present history lasted for more than 1 year and had poor response to immunotherapy were retrospectively collected.HT was screened in these patients by adopting next generation sequencing (NGS). Finally, clinical and laboratory characteristics of these children with HT were summarized and analyzed. Results A total of 161 children with chronic thrombocytopenia were included.Forty-three cases (26.7%) were found to have gene mutations.The genetic rules of the mutant gene, the family verification and the clinical manifestations of the proband and some related laboratory tests were analyzed and 24 cases (14.9%) can be diagnosed as HT.Among the HT patients, the proportion of males and females was 159, and the median onset of age was 0.58 years, which was significantly lower than that of non-HT cases (the median onset of age was 4.36 years), and the difference was statistically significant (P<0.001); the proportion of mucosal hemorrhage and visceral hemorrhage (31.8% and 13.7%) of HT was significantly higher than non-HT cases (15.3% and 0.6%), and the difference was statistically significant (P<0.001). Fifty percent of (12/24 cases) cases of HT had positive family history; according to the ave-rage platelet volume and platelet morphology in peripheral blood smear, HT could be divided into small platelet HT, po-sitive platelet HT and large platelet HT.Some cases had well response to immunotherapy but seemed easy to relapse du-ring the withdrawal period, while the others responded poorly to therapy.Different clinical manifestations of HT suggest different pathogenesis, which can be divided into the related types of megakaryocyte differentiation defect, megakaryocyte maturation defect, platelet release defect and platelet survival time shortening. Conclusions The pathogenesis and cli-nical phenotype of HT was different.Some of them were effective for immunotherapy, which were easily confused with immune thrombocy-topenla(ITP). It is clinically necessary to perform NGS in children with thrombocytopenia at early onset, abnormal platelet morphology, prolonged disease course or severe mucosal/visceral hemorrhage, in order to recognize HT timely to avoid delay in diagnosis and poor prognosis. Key words: Child; Hereditary thrombocytopenia; Next generation sequencing