FISH Analysis in Taiwanese Children with Suspected Diagnosis of Williams Syndrome

Williams syndrome (WS) is a contiguous gene syndrome caused by deletion of chromosome 7q11.23 involving the elastin gene. This study aimed to use the fluorescent in situ hybridization (FISH) to detect the elastin gene deletion in Taiwanese children with suspected diagnosis of WS. Thirty four children (22 boys, 12 girls; median age 1.9 years, age range: 2 day to 16.8 years) with suspected diagnosis of WS including a typical dysmorphic face, mental retardation, supravalvular aortic stenosis (SVAS) or peripheral pulmonary stenosis (PPS) were studied. Metaphase chromosome slides were prepared from peripheral blood. FISH was performed using the chromosome 7q11.23 probe for elastin gene and control probe for chromosome 7q31. FISH was positive in 82% (28/34) patients with suspected WS, 100% (27/27) patients with typical dysmorphic face and mental retardation and 14% (1/7) patients with SVAS or PPS. Microdeletion of elastin gene was positive in all typical WS patients but only in 14% patients with SVAS or PPS.