Williams-Beuren syndrome in the Hong Kong Chinese population: retrospective study.

OBJECTIVE: To estimate the incidence and document the clinical characteristics of Williams-Beuren syndrome in the Hong Kong Chinese population.

DESIGN: Cytogenetic analysis and retrospective study.

SETTING: Clinical Genetic Service, Department of Health, Hong Kong.

PATIENTS: Forty-one Chinese patients with Williams-Beuren syndrome.

MAIN OUTCOME MEASURES: From 1 January 1995 to 30 June 2002, fluorescence in situ hybridisation was used to confirm diagnoses in 41 cases of Williams-Beuren syndrome by detecting chromosome 7q microdeletion. Case records were reviewed, the incidence of the condition in the local population was estimated, and the main clinical characteristics were determined.

RESULTS: The minimal incidence of Williams-Beuren syndrome in this locality was estimated to be approximately 1 per 23500 live births. Common dysmorphic facial features included periorbital fullness (83%), full lips (80%), a long philtrum (51%), a flat nasal bridge (41%), and abnormal teeth (37%). No patients had a stellate iris. The majority (82%) had at least one documented cardiac anomaly; among these patients, peripheral pulmonary stenosis was diagnosed in 61% and supravalvular aortic stenosis in 45%. Nearly all (93%) of the study group exhibited developmental delay.

CONCLUSION: As in the West, patients with Williams-Beuren syndrome in the Hong Kong Chinese population display craniofacial dysmorphism, cardiovascular anomalies, and mental deficiency. Supravalvular aortic stenosis-the cardiac defect most commonly associated with Williams-Beuren syndrome in western countries-is less common than peripheral pulmonary stenosis in this region. Studies involving periodic cardiovascular evaluation are needed to confirm if this difference is significant.