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 m RNA levels of HRH4 were examined. ELISA was used to measure the levels of Ig E 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 1.30-2.63), whereas deletions of HRH4 copy numbers were not associated with disease risk for AD ( P = 0.30, OR = 0.82, 95% CI 0.57-1.19). HRH4 m RNA levels were much higher in samples with HRH4 copy-number amplifications than in those without such amplifications ( P < 0.05). Ig E levels were associated with amplifications ( P < 0.05, OR = 1.96, 95% CI 1.19-3.25), but not with deletions ( P = 0.63, OR = 0.87, 95% CI 0.49-1.54) of HRH4 copy numbers. Conclusions CNVs of the HRH4 gene are associated with AD in a Chinese population. [ABSTRACT FROM AUTHOR]