GMPPB and Crohn disease: The Parkinson’s disease risk locus at IP6K2 is also noteworthy for its association with expression of candidate Parkinson’s disease gene WDR6 and four other genes (NCKIPSD, GMPPB, PRKAR2A, and AMT) in both colon and substantia nigra.42 Intriguingly, the IP6K2 was shown to confer ambiguous pleiotropy for Parkinson’s disease-Crohn’s disease in our present work and needs subsequent studies to follow-up.