HTRA2 and rheumatoid arthritis: As would be expected, the genes identified in this study have been implicated in the smoking-associated conditions osteoporosis (LRP5), inflammatory bowel disease (CPAMD8, GRP68), cognitive disorders (AVPR1B, SYNJ2), male infertility (AHRR), Parkinson’s (HIVEP3, HTRA2), rheumatoid arthritis (CD247), atherosclerosis (AHRR) and a wide array of cancers (many genes).