A systems-based approach combining expression quantitative trait loci (eQTL) studies from cerebellum and frontal cortex of AD patients, GWAS from AD and PD and PPI networks indicated that some PD variants (cisSNPs, cis-acting SNPs) were associated with the expression of CRHR1, LRRC37A4 and MAPT located at 17q21 and suggestive of AD risk (Liu et al., 2015). This evidence concerns the gene MAPT and Alzheimer disease.