INCREASED RISK OF PARKINSONS-DISEASE IN PARENTS AND SIBLINGS OF PATIENTS

We studied the incidence of Parkinson's disease in 586 first-degree re latives (parents and siblings) of 114 randomly ascertained white patie nts with idiopathic Parkinson's disease and in 522 first-degree relati ves of 114 age-matched unrelated white control subjects. Sixteen perce nt of patients had a family history as compared to 4% of control subje cts (p < 0.01). The age-specific cumulative incidence was higher in th e first-degree relatives of patients than in the first-degree relative s of control subjects (p = 0.007). The age-adjusted odds ratio was 3.5 (95% confidence interval: 1.3-9.4; P = 0.014). These results suggest that genes contribute to the etiology of Parkinson's disease.