According to a current database (OMIM #311800), PGK-1 lies on the X chromosome at 78,065,188–78,129,296, a region within Xq21.1, although PGK-1 was originally reported to map to chromosome Xq13.7 Interestingly, the region between Xq21 and q25 is known as a susceptibility locus for classical PD associated with PARK12 (OMIM #300557), and the causative gene for this disease has not been identified.8, 9 We therefore speculate that mutations in PGK-1 may contribute to the pathogenesis of PARK12-associated PD. Here, PGK1 is linked to Parkinson disease.