Importance of molecular techniques in diagnosing Williams-Beuren syndrome

Abstract

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.