Coding polymorphisms in the parkin gene and susceptibility to Parkinson disease.

BACKGROUND Mutations in the parkin gene, an E3 protein-ubiquitin ligase, cause autosomal recessive early-onset Parkinson disease (PD). The role of polymorphisms in the parkin gene as risk factors for PD is still unclear, as the results in the literature are contradictory. PATIENTS We compared the allele and genotype frequencies of the Ser167Asn, Arg366Trp, Val380Leu, and Asp394Asn polymorphisms in 194 patients with PD (92 familial and 102 sporadic) and 125 control subjects. RESULTS Homozygous Val380 was significantly associated with sporadic PD (P =.008). There was also a trend toward an association of homozygous Asp394 with familial PD (P =.07). CONCLUSIONS Some parkin polymorphisms appear to be risk factors for sporadic or familial PD. The functional effects of these coding polymorphisms need to be established, and further studies on parkin polymorphisms in PD should be undertaken.