Non-replication of association between MAPT-SNCA synergistical interaction and susceptibility to Parkinson’sDisease in a southern European population

The combination of MAPT H1H1 genotype and SNCA (rs356219) GG genotype interaction has recently been identified as a possible factor to approximately double the risk for development of PD. The objective of our study was to test the association of the interaction of these two genetic variants with Parkinson’s disease in a southern European case-control study. We analysed MAPT haplotypes and performed SNP genotyping with Taqman assays for the SNCA rs356219 marker in cohorts of 352 patients and 417 controls of Greek and Italian origin, respectively. Cases (n=352) were more often homozygotes for the MAPT H1 haplotype than controls (n=417). However, the association of the SNCA rs356219 G allele or GG homozygotes with Parkinson’s disease was not confirmed. Furthermore the interaction of the SNCA GG genotype with MAPT H1H1 genotype was not proved to be increased among cases with Parkinson’s disease compared to the controls. The data suggest that increase of PD risk by this specific combination of genotypes is not reproducible to all PD populations.