AHR and allergic disease: CYP1B1 is a member of the cytochrome P450 superfamily of enzymes and performs ligand degradation in aryl hydrocarbon receptor (AHR)-dependent signalling pathway.46 AHR-dependent signalling pathway plays important roles in the immune response to molecular changes provided by the environment, diet, commensal flora and host metabolism.47 The missense variants of CYP1B1 are involved in developing allergic diseases through the dysregulation of immune responses to external molecules.