Machado-Joseph disease: cerebellar ataxia and autonomic dysfunction in a patient with the shortest known expanded allele (56 CAG repeat units) of the MJD1 gene.

We describe an unusual case of a patient with Machado-Joseph disease (MJD) who showed autonomic dysfunctions in addition to cerebellar ataxia. The number of CAG repeat units in the expanded allele of the MJD1 gene of the patient is smaller (56 CAG repeat units) than all previously reported numbers of CAG repeat units in expanded alleles. Thus, the findings in this patient indicate that the clinical features of MJD cover a wider spectrum than previously thought.