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 23 500 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.

Key words: Abnormalities, multiple; Genetic disease, inborn; Williams syndrome

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