STX1B and Parkinson disease: However, the recent collaborative study of the IPDGC and WTCCC2 on a dataset of post-mortem brain samples assayed for gene expression (n = 399) and methylation (n = 292), revealed methylation and expression changes associated with PD risk variants in PARK16/1q32, GPNMB, and STX1B, suggesting that the SNCA gene is unlikely to be the only one subjected to epigenetic regulation in PD brains [68].