Gender ratio differences between Parkinson's disease patients and their affected relatives

Mitochondrial dysfunction in Parkinson's disease (PD) is suspected to arise from either acquired or inherited mutation of mitochondrial DNA (mtDNA), I f inherited, epidemiologic analysis may reveal maternal transmission. We lo oked for maternal inheritance bias in our PD clinical database. About 13% o f 600 PD probands reported an affected parent. Although 60% of the PD proba nds were male, only 42% of the affected parents were. The gender ratios for the proband and affected parent generations were dissimilar (p < 0.005), i ndicating an under representation of affected fathers or an overrepresentat ion of affected mothers. To address these possibilities we analyzed a non-P D control cohort. Four percent of the controls had a PD affected parent, an d 75% of these affected parents were male. Apparent maternal inheritance bi as in our PD cohere is therefore more likely due to overrepresentation of a ffected mothers, and is consistent with mitochondrial inheritance in some o f our ascertained cases. (C) 2001 Elsevier Science Ltd. All rights reserved .