Importance of molecular techniques in diagnosing Williams-Beuren syndrome

Abstract

Iravathy Goud .K1*, Dayakar.S1, Babu.S.J 1, Vijaya Lakshmi .K1, Peter Miny2, Friedel Wenzel3,Dharmendra Jain4, Vimarsh Raina4

Williams’s syndrome is a complex syndrome characterized by developmental abnormalities,craniofacial dysmorphic features, and cardiac anomalies. Clinical diagnostic criteria are available for WS; the mainstay for diagnosis is detection of the contiguous gene deletion of the Williams-Beuren syndrome critical region (WBSCR) that encompasses the elastin (ELN) gene which can be detected using fluorescent in situ hybridization (FISH) or targeted mutation analysis.A two and half year old child was referred to our Molecular Biology and Cytogenetic lab for cytogenetic analysis which revealed normal male karyotype. As the diagnosis could not be confirmed the sample was further tested for WBS critical region - ELN-locus in 7q11 by FISH analysis. Loss of ELN-locus in 7q11 confirmed the clinical diagnosis of WBS in the child. The parents of the child benefited enormously by learning that the risk of recurrence was < 1% as this microdeletion occurs sporadically (new mutation). The main aim of this study is to emphasize on two aspects: (i) the importance of making use of modern molecular techniques to diagnose such a syndrome and (2) the difficulties faced by the physician to provide appropriate diagnosis and the adequate genetic counseling to such patients due to the lack of such molecular facilities.