Genetics of Parkinson's disease

Abstract

The hypothesis that heredity plays an important role in the etiology of PD has long seemed attractive. It was initially suggested by positive family histories and later by reports of kindreds of "parkinsonism." It was reinforced by the first systematic family study of PD conducted a half-century ago by Mjones. However, closer study of the clinical data indicates that familial aggregations of parkinsonism have reflected various other disorders, notably OPCA and other forms of multiple system atrophy. Case control studies have failed to document a prevalence of PD among first-degree relatives of index cases significantly exceeding that found in control groups. More recently, the concordance rate for PD among monozygotic twins has been found to be unexpectedly low and not significantly different from that among dizygotic twins or the prevalence among first-degree relatives. Thus, the best available data do not support a role of heredity in the etiology of PD. A nonhereditary, possibly congenital genetic defect is, however, not excluded.