CYP2A13 and asthma: Some of these pathways including “Drug metabolism – other enzymes”, “Chemical carcinogenesis – DNA adducts”, and “metabolism by xenobiotics by cytochrome P450”, which include genes involved in cytochrome P450 metabolism (e.g., CYP1A1, CYP2E1, CYP2A13), glutathione metabolism (GST family genes), and glucuronidation (UGT family of genes); these pathways have all reported to have some role in asthma [30–33].