Is there a genetic susceptibility to idiopathic parkinsonism?

The search for the etiology of idiopathic parkinsonism (IP) has been difficult and largely unsuccessful. Recently, there has been renewed interest in the possibility that there are genetic susceptibility loci for IP. Part of this interest has been spurred by recent advances in molecular genetics. This review analyzes the available genetic epidemiology and family study data (clinical and molecular genetic) as they relate to IP and parkinsonism plus syndromes (PPS). Analysis of data from families with several members having IP or PPS suggests that this approach may not identify susceptibility genes for IP. When the genes responsible for the syndromes affecting multiplex families are identified, they are likely to provide insight into the pathogenesis of IP and may be the basis for developing a more useful nosology. The molecular genetic study of PPS and the mapping of the wld locus may herald rapid advances in understanding these syndromes.