CHRNA4 and Norrie disease: In our evaluation of GSCAN-identified loci, we corroborated associations of several previously implicated loci for ND (e.g., nicotine acetylcholine receptors genes CHRNA5-A3-B4 and CHRNA4) and three additional loci (DRD2, C16orf97, and CHRNB2) that have not been reported in prior ND GWAS.