Association analysis of brain-derived neurotrophic factor gene polymorphisms in asthmatic children.

Brain-derived neurotrophic factor (BDNF) has been described to modulate airway hyper-responsiveness and inflammation and was involved in late allergic reaction in asthma and higher levels of circulating BDNF were present in allergic asthmatics. In BDNF gene, Val66Met and C-270T polymorphisms were described. There were, however, very few studies analyzing BDNF gene polymorphisms in asthma. The aim of this study was to analyze the possible relationship between these two polymorphisms in the BDNF gene and asthma. Fifty-six pediatric asthmatic patients were analyzed, aged from 6 to 18. The diagnosis of atopic asthma was based on clinical manifestation, lung function test and increased immunoglobulin E level, and/or positive skin prick tests. The control group consisted of 109 healthy subjects. The polymorphisms were genotyped with the use of polymerase chain reaction-restriction fragment length polymorphism method. We did not observe an association of Val/Met polymorphism and the presence of asthma. However, we observed that Val allele is much more frequent in the male group of asthmatic patients (p = 0.06). For -270C/T polymorphism, we found significant differences between asthmatic patients and the control group (p = 0.041 for genotypes and p = 0.005 for alleles). The results may suggest a relationship between the BDNF gene and asthma and male gender of asthmatic children.