[Clinical and genetic analysis of 188 families with spinocerebellar degeneration. Friedreich's disease and P. Marie's hereditary ataxias].

Based on the hereditary ataxias concepts and a large field survey, the authors analyzed 392 cases of spino-cerebellar degeneration belonging to 188 families. Two main clinical groups were identified: 227 cases of Friedreich ataxia and 74 cases of cerebellar hereditary ataxia of P. Marie type. The association in the same patient of peroneal atrophy of Charcot Marie type with Friedreich ataxia (17 cases) or P. Marie cerebellar hereditary ataxia (13 definite cases and 13 probable) was the most striking finding. "Forme fruste", incomplete form or complex form of Friedreich ataxia were present in some families while in some others there was spastic paraplegia or pure Charcot Marie Tooth disease. This clinical heterogeneity in families of spino-cerebellar degeneration is discussed.