Frequência e caracterização clínica de indivíduos com púrpura trombocitopênica imunológica da Fundação de Hematologia e Hemoterapia do Estado do Amazonas testados citogeneticamente para a Síndrome de Deleção do 22q11.2.

Abstract

The thrombocytopenia arise in peripheral blood when the destruction, utilization or sequestration of platelets exceeds the spinal cord ability to produce them. Among the causes of thrombocytopenia there is the immune thrombocytopenic purpura (ITP), a condition characterized by the formation of autoantibodies against human platelet antigen system. PTI is considered one of the findings described in the broad clinical spectrum of the 22q11.2 deletion syndrome (22q11.2DS), Also known as DiGeorge syndrome or velocardiofacial, the 22q11.2DS is an autosomal dominant condition with variable expressivity, caused by a deletion involving the region 11.2 of the long arm (q) of chromosome 22. It has an estimated prevalence of 1 per 2000-4000 live births, making it one of the most common genetic diseases in humans. The diagnosis has some limitations, high-resolution karyotype, for instance, has limitations because it is able to identify less than 15% of affected patients (most patients have a very small deletion - A microdeletion - that escapes detection by this test). Therefore, the test considered most suitable for the diagnosis is the fluorescence in situ hybridization (FISH), a molecular cytogenetic technique which uses DNA probes marked with fluorescent material. FISH is capable of detecting more than 90% of cases. Knowing that Foundation of Hematology and Hemotherapy of the State of Amazonas (HEMOAM) is a referral center in the state in the evaluation and treatment of patients with ITP, the aim of this study was to evaluate the frequency and clinical characteristics of individuals with 22q11.2DS among patients diagnosed with ITP in this institution. Keywords: Hematological alterations, Thrombocytopenia, immune thrombocytopenic purpura, deletion syndrome 22q11.2, velocardiofacial syndrome, DiGeorge syndrome, Fluorescence in situ hybridization