Association between copy-number variations of the human histamine H4 receptor gene and atopic dermatitis in a Chinese population

Background Atopic dermatitis (AD) is a chronic, relapsing allergic skin disease. The histamine H4 receptor (HRH4) has been shown to be associated with a number of autoimmune disorders, including AD. Aim To explore a possible association between copy-number variations (CNVs) of the HRH4 gene and the risk of AD in a Chinese population. Methods Genomic DNA and RNA were collected from 541 patients with AD and 613 healthy controls, and the CNVs and mRNA levels of HRH4 were examined. ELISA was used to measure the levels of IgE in all participants. Results Amplifications of HRH4 copy numbers were associated with the risk of developing AD (P<0.05, OR=1.85, 95% CI 1.302.63), whereas deletions of HRH4 copy numbers were not associated with disease risk for AD (P=0.30, OR=0.82, 95% CI 0.571.19). HRH4 mRNA levels were much higher in samples with HRH4 copy-number amplifications than in those without such amplifications (P<0.05). IgE levels were associated with amplifications (P<0.05, OR=1.96, 95% CI 1.193.25), but not with deletions (P=0.63, OR=0.87, 95% CI 0.491.54) of HRH4 copy numbers. Conclusions CNVs of the HRH4 gene are associated with AD in a Chinese population.