MTNR1A is a 7-transmembrane protein belonging to the GPCR superfamily and plays an important role in regulating the central nervous and immune systems in mammals.[24] Chloe Sarnowski et al performed a series of genetic analyses of asthma and observed that methylation within MTNR1A gene mediated the effect of paternally-inherited variants on the comorbidity of asthma and allergic rhinitis.[25,26] MTNR1A is involved in the regulation of circadian rhythms and sleep-wake cycles. The gene discussed is MTNR1A; the disease is allergic rhinitis.