We found associations between hippocampal volume reductions in AD subjects and the EFNA5 (ephrin-A5), ARSB (arylsulfatase B), MAGI2 (membrane associated guanylate kinase, WW and PDZ domain containing 2), PRUNE2 (prune homolog 2), and CAND1 (cullin-associated and neddylation-dissociated 1) genes. The gene discussed is EFNA5; the disease is Alzheimer disease.