Onset and progression of disease in familial and sporadic Parkinson's disease.

Lately different and rare genetic forms of Parkinson's disease (PD) have been described. Complete genomic screening has suggested that still undefined multiple genetic factors might underlie the development of PD. The course of PD patients with and without genetic background might be different. We compared the age at onset and progression of PD with (FH) and without (NFH) family history. Two hundred forty PD patients attending the outpatient Movement Disorders Clinic were evaluated. The age of onset (AO), the duration of disease until stage III of Hoehn and Yahr (YST3), until dementia (YDEM) and family history of PD were determined by interview, examination of medical files and of affected family members. Patients with young onset who reported another PD patient among their siblings were tested for parkin mutations. Statistical analysis used ANOVA, Fisher's Least Significant Difference, log-rank and Wilcoxon's tests for Kaplan-Meier survival curves taking stage III and dementia as end-points. Of the 240 patients (age 73.3 +/- 10.9 years), 29 (12%) had positive FH. Six of them carried parkin mutations. The AO was 33.5 +/- 8.1 (range 19-42) years for parkin carriers, 59.3 +/- 11.3 (range 34-76) for FH and 66.5 +/- 11.8 (27-91) years for NFH (P < 0.0001). The three groups were significantly different from each other (alpha = 0.05). Stage III and dementia were reached only in non-parkin patients. YST3 was 12.6 +/- 6.6 years for FH and 6.5 +/- 5.0 years for NFH (P < 0.0001). YDEM was 10.1 +/- 6.0 years for FH versus 4.7 +/- 4.5 years for NFH (P = 0.002). Kaplan-Meier survival analysis revealed faster motor (P = 0.0016) and mental decline (P = 0.02) in NFH versus FH. Our results showed that the AO of PD is younger in patients with FH. Motor and mental deterioration, however, showed a less steep course in familial PD patients.