The occurrence of Crohn's disease was found to be associated with a mutation at the AhR gene rs2158041 in the Chinese population (23), whereas xeroderma (24), rheumatoid arthritis (25), glioma (26), and vitiligo (27) have been associated with polymorphisms in the SNPs of the AhR gene. The gene discussed is AHR; the disease is rheumatoid arthritis.