In a territory-wide survey of Huntington's disease (HD) in the Chinese population of Hong Kong, 20 patients from 11 families were identified from 1984 to 1991, giving a low period prevalence of 3.7 per 10(6) population. Six patients had died by 1991, hence the point prevalence was even lower, being 2.5 per 10(6) population. The male to female ratio was 3:1. No paternal transmission effect on the age of onset was observed. Apart from these differences, the clinical and pathological features were similar to those seen in the West.