TMEM175 and Parkinson disease: Examining the TMEM175 locus PD GWAS signal found the rs34311866 missense SNP (p.M393T) in TMEM175 to be the most significant variant in the region by over 20 orders of magnitude (P = 1.47E − 50, OR = 1.232, SE = 0.014) (Fig. 1A).