title: Hematological abnormalities and 22q11.2 deletion syndrome.
abstract: The 22q11.2 deletion syndrome (22q11DS) is a common genetic disease characterized by broad phenotypic variability. Despite the small number of studies describing hematological alterations in individuals with 22q11DS, it appears that these abnormalities are more frequent than previously imagined. Thus, the objective of our study was to report on a patient with 22q11DS presenting thrombocytopenia and large platelets and to review the literature. The patient, a 13-year-old boy, was originally evaluated due to craniofacial dysmorphia and speech delay. He also had a history of behavioral changes, neuropsychomotor delay and recurrent otitis/sinusitis. The identification of a 22q11.2 microdeletion by fluorescent in situ hybridization diagnosed the syndrome. Despite his hematological alterations, he only had a history of epistaxis and bruising of the upper and lower limbs. Assessments of the prothrombin time, thrombin time, partial thromboplastin time, bleeding time, fibrinogen levels and platelet aggregation (including the ristocetin induced platelet aggregation test) were all normal. Hematological alterations observed in 22q11DS are directly related to the genetic disorder itself (especially in respect to deletion of the GPIb gene) and secondary to some clinical findings, such as immunodeficiency. Macrothrombocytopenia is increasingly being considered a feature of the broad spectrum of 22q11DS and may potentially be a clinical marker for the syndrome.
authors.affiliation: Clinical Genetics Section, Pathology Department, Universidade Federal de Ciências da Saúde de Porto Alegre - UFCSPA - Porto Alegre, RS, Brazil.
authors.forename: Rafael Fabiano Machado
authors.initials: RF
authors.lastname: Rosa
authors.forename: Rosana Cardoso Manique
authors.initials: RC
authors.lastname: Rosa
authors.forename: Pedro Paulo Albino
authors.initials: PP
authors.lastname: Dos Santos
authors.forename: Paulo Ricardo Gazzola
authors.initials: PR
authors.lastname: Zen
authors.forename: Giorgio Adriano
authors.initials: GA
authors.lastname: Paskulin
keywords: Bernard-Soulier syndrome; Blood platelets; Chromosomes, Human, Pair 22; DiGeorge syndrome; In situ hybridization; Thrombocytopenia