15 Dec 2000

Mutations in the genes for α-synuclein and parkin have been linked to early onset Parkinsonism, but the role of genetics in the far more common late-onset disease has been less clear. Now an analysis of families in Iceland indicates that there is a genetic factor in late-onset Parkinson's disease. The study, led by Kari Stefansson, analyzed the medical records of 772 living and deceased patients in whom the disease had been diagnosed during the previous 50 years. Then, using an extensive geneological database of the Icelandic population, the researchers determined whether the Parkinson's patients were more closely related to one another than were random members of the population. The study found the patients were indeed significantly more related to each other than were subjects in matched groups of controls. The risk ratio for Parkinson's disease was 6.7 (95 percent confidence interval, 4.3 to 9.6) for siblings, 3.2 (95 percent confidence interval, 1.2 to 7.8) for offspring, and 2.7 (95 percent confidence interval, 1.6 to 3.9) for nephews and nieces of patients with late-onset Parkinson's disease. The reseachers conclude that there is a genetic component to late-onset Parkinson's.—Hakon Heimer