PRRG4 and Parkinson disease: The most strongly associated SNP, rs10767971, located on chromosome 11 between the genes QSER1 and PRRG4, was associated with a 3.2 year older PD onset in individuals with 2 copies of the minor allele (p = 5.4 × 10-7 in the 3 sample meta-analysis, compared to 4.3 × 10-6 in the 2 sample meta-analysis).