COLQ and dentin dysplasia: In the combined analysis of these sample sets, three genetic loci that show genome wide-significance and may be associated with the risk of DD and/or diverticulitis were identified: intronic variants at the ARHGAP15 (Rho GTPase-activating protein 15), COLQ (collagen-like tail subunit of asymmetric acetylcholinesterase) and FAM155A (family with sequence similarity 155 A) loci were significantly associated with DD.