PKN2 and osteopetrosis: At seven loci, there was a single putative causal gene: Abca12 at a locus for adult neurogenesis; Epha4 (stress-coping strategy); Pkn2, Slit3, and Pgk1-rs7 (at three different loci for sleep); H60c (home cage activity); and Adcy1 (osteopetrosis).