A large Japanese family with Machado-Joseph disease: clinical and genetic studies.

A large Japanese family with probable Machado-Joseph disease (MJD) is described. Detailed neurological examination in 12 patients from 3 generations revealed variable combinations of cerebellar ataxia, ocular paresis, difficulty in eye-lid opening, bulging eyes, facial "myokymia", facial dystonia, pyramidal signs, extrapyramidal signs, and peripheral neuropathy. Mode of inheritance was in all likelihood autosomal dominant. Blood components were typed for 19 conventional chromosome markers. Although association of the affected members with the PGM1 system was high, linkage analysis failed to reveal any markers studied with a lod score higher than 3. The unique constellation of symptoms appeared sufficient to rule out other types of spinocerebellar degeneration. When there is a typical case in a given family, MJD appears to be a clinically recognizable entity.