Evidence for More than One Parkinson’s Disease- Associated Variant within the HLA Region

Parkinson’s disease (PD) was recently found to be associated with HLA in a genome-wide association study (GWAS). Follow-up GWAS’s replicated the PD-HLA association but their top hits differ. Do the different hits tag the same locus or is there more than one PD-associated variant within HLA? We show that the top GWAS hits are not correlated with each other (0.00#r2#0.15). Using our GWAS (2000 cases, 1986 controls) we conducted step-wise conditional analysis on 107 SNPs with P,1023 for PD-association; 103 dropped-out, four remained significant. Each SNP, when conditioned on the other three, yielded PSNP1 = 561