Joseph disease in India--report of two families.

Joseph disease (JD) has only rarely been described in families of non-Portuguese ancestry. Two Indian families with an autosomal dominant inherited ataxia are described in this report. The clinical picture resembled the spectrum seen in JD. An interesting feature was the very early manifestation of the disease process in the third generations. Considerable phenotypic variation within one family was another important aspect. These families had always lived in northern India for the past many generations.