Familial parkinsonism: Our experience and review.

There is substantial interest in the possible role of genetic factors in the etiology of idiopathic parkinsonism (IP) and parkinsonism-plus syndromes (PPS). We have longitudinally investigated eight large kindreds from North America. Five families demonstrated IP features, two families represented PPS and in one family, neither a diagnosis of IP or PPS could be established. A literature review supported our findings; only half of the published kindreds presented with a clinical picture typical of IP. Genetic DNA analysis is in progress on our kindreds and on many families in our literature review. The results may clarify the etiology and classification of IP and PPS.