Recently, numerous genome-wide association studies have been published for AD, and many AD susceptibility loci have been identified, such as APOE, LRAT, APOC1, SORL1, GAB2, PGBD1, CHRNB2, CLU, PICALM, CR1, PCDH11X and TRPC4AP [7-17]. The gene discussed is PCDH11X; the disease is Alzheimer disease.