Phenotypic Commonalities in Familial and Sporadic Parkinson Disease

The increased incidence of parkinsonism in men with familial PD suggests that the sex disparity is more likely the result of a protective effect against development of PD in women than of an increased risk in men that is associated with environmental factors. Phenotypic similarity among familial and sporadic PD indicates that a similar topographic distribution of the nigrostriatal lesion exists in patients with either form of PD regardless of apparent genetic influence.