Background: Mutations in the parkin gene cause autosomal recessive early-onset parkinsonism. The effect of single heterozygous mutations in parkin is still unclear. The aim of the present study was to evaluate the frequency of exonic parkin variants in a case-control study.
Methods: The parkin gene was screened for both point mutations and exon rearrangements in 172 isolated French patients with Parkinson’s disease (PD) and 170 controls from the same population. Patients with single parkin variants were also screened for PINK1, DJ-1 and LRRK2 exon 41 mutations.
Results: We identified 10 exonic sequence variations, including 3 known polymorphisms and 7 rare heterozygous variants, 2 of which were novel. There were significantly more rare heterozygous variants in patients (n=10) with early-onset parkinsonism than in controls (n=2). The screening of PINK1, DJ-1 and LRRK2 exon 41 in the 10 heterozygous parkin patients failed to identify a second causative mutation.
Conclusion: Our results suggest that single parkin mutations increase the risk of early-onset PD, but we cannot exclude that a second parkin mutation has been missed.
- Parkinsons disease
- case-control study
- early-onset parkinsonism
- heterozygous parkin variants