[22q11.2 deletion syndrome: importance of clinical evaluation and FISH analysis]

Abstract

Objective: The 22q11.2 deletion syndrome nowadays is considered one of the most often observed genetic diseases in humans. It is clinically characterized by a rather wide phenotypic spectrum, with more than 180 clinical features physical as well as behavioral, already described. However, none is pathognomonic or obligatory which makes diagnosis even more difficult. Thus, this study intended to determine the prevalence and clinical characteristics of patients with 22q11.2 microdeletion in a selected sample of subjects with clinical suspicion of 22q11.2 deletion syndrome and normal karyotype.

Methods: A selected sample of 30 patients with clinical suspicion of 22q11.2 deletion syndrome and normal karyotype was evaluated by application of a standard clinical protocol and cytogenetic analysis with fluorescent in situ hybridization.

Results: 22q11.2 microdeletion was identified in 3 patients (10%), a prevalence similar to the majority of published studies, which ranged from 4 to 21%. The 22q11.2 deletion syndrome patients in this study were characterized by a variable phenotype and shared few clinical features, in agreement with the literature description.

Conclusions: These findings strengthen the idea that clinical diagnosis of 22q11.2 deletion syndrome is difficult due to the large phenotypic variability. Therefore a detailed clinical evaluation associated to a sensitive test such as fluorescent in situ hybridization analysis is crucial for the identification of these patients.