Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) was originally described among French Canadians in the Charlevoix-Saguenay-Lac-Saint-Jean region of Quebec (OMIM 270550).¹ The gene responsible for ARSACS was identified as sacsin, and frameshift (8585 deletion T, 2805X) and nonsense (C7245T, R2355X) mutations were reported in Quebec.² Recently, patients with other mutations have been described in countries elsewhere.³ These showed not only the spastic ataxia with peripheral neuropathy recognised in Quebec, but some additional features as well.³ Here we describe a female Japanese ARSACS patient with a novel nonsense mutation (C3774T, Q1198X), which resulted in a shorter truncated protein than those of the French Canadian patients. We report the details of her clinical and genetic data, and discuss the correlation between mutations and phenotypes in ARSACS.

The patient was a 39 year old woman who first walked at 12 months. Her gait was normal in early childhood. A spastic gait started at nine years of age, but she made no complaint about it for many years. After the age of 35 she complained of unsteadiness in her gait and clumsiness in her hands. Her gait disturbance progressed and she visited our clinic at the age of 37.

Consanguinity was not identified in her parents. Family members (parents and one brother) and other relatives have …