Brain-derived neurotrophic factor gene polymorphisms and serum levels in Chinese atopic dermatitis patients

Background Brain-derived neurotrophic factor (BDNF) plays an important role in the pathogenesis of atopic dermatitis (AD). Whether BDNF gene polymorphisms are associated with Chinese AD remains totally unknown. Objective The aim is to determine if BDNF gene C270T and G196A polymorphisms are associated with Chinese AD, and analyse the clinical relevance of BDNF gene polymorphisms and BDNF serum levels. Methods We conducted a case-control association analysis (160 patients and 169 controls) in Northern Chinese subjects. Genotyping was performed by restriction fragment length polymorphism, and serum levels of BDNF were measured using enzyme-linked immunosorbent assay. Results For C270T, there were significant differences in C/T genotype distribution (P = 0.003) and T allele frequencies (P = 0.004) between AD patients and controls in the whole dataset. Higher C/T genotype frequencies were found in male AD (10.6% vs. 1.1%, P = 0.018) and in intrinsic AD (IAD; 15.79% vs. 2.91%, P = 0.008). No association between G196A polymorphism and AD was observed in the whole cohort, while A allele was much more frequent in AD patients with atopy in first-degree relatives (65.8% vs. 34.2%, P = 0.038). Serum BDNF levels were correlated with IAD severity as measured by Scoring Atopic Dermatitis index (r = 0.576, P < 0.001). Conclusion T allele in C270T may be a risk factor for AD, especially in IAD and male AD. A allele in G196A may be a risk factor in AD patients with atopy in first-degree relatives. Serum BDNF levels were correlated with the severity of IAD.