OBJECTIVE:

To assess the frequency and clinical features of different types of hereditary spinocerebellar ataxia in Hong Kong.

DESIGN:

Cross-sectional study using a questionnaire and clinical examination, with the majority of the information retrospectively collected.

SETTING:

Three regional hospitals, Hong Kong.

PARTICIPANTS:

All patients with spinocerebellar ataxia that was confirmed by molecular genetic tests between January 2001 and October 2003.

MAIN OUTCOME MEASURES:

History, latest physical examination results, clinical investigation results, and genetic profiles.

RESULTS:

A total of 16 Chinese patients had received diagnoses of spinocerebellar ataxia. These patients had spinocerebellar ataxia type 1 (n=3), spinocerebellar ataxia type 3 (Machado-Joseph disease; n=12), and dentatorubro-pallidoluysian atrophy (n=1). The most common manifestation was ataxia (15/16), followed by pyramidal signs (12/16). Other features such as bulbar dysfunction, ophthalmoplegia, neuropathy, and cognitive impairment were present but variable.

CONCLUSIONS:

The clinical manifestations of different types of spinocerebellar ataxia overlap, and genetic study is necessary to confirm the diagnosis. The frequency of spinocerebellar ataxia type 3 is greater than that of other types among these Chinese patients. The age of onset of this type may correlate inversely with the number of CAG repeats.