RPGR and Cowden disease: ,39,40,45,46 For example, a genetic analysis of X-linked CD among 2 families of Northern European decent by Yang et al. linked the associated mutations to chromosomal locus COD1, which maps to a region harboring RPGR, and identified 2 mutations in RPGR ORF15 (ORF+1343_1344delGG and ORF+694_708del15) that were present in affected individuals but not in control subjects.45