The relationship between the level of vitamin D and vitamin D receptor gene polymorphism in childhood asthma

ABSTRACT THE RELATIONSHIP BETWEEN THE LEVEL OF VITAMIN D AND VITAMIN D RECEPTOR GENE POLYMORPHISM IN CHILDHOOD ASTHMA Asthma is the most common chronic disease of childhood and is in large part attributable to genetic factors. Vitamin D and its nuclear receptor (VDR) are linked to asthma in a genetic and immunologic basis. Polymorphisms in the VDR gene may alter the actions of vitamin D and then influence the development of asthma. In this study, the associations of serum vitamin D levels and VDR gene polymorphisms with childhood asthma were evaluated. We aim at to gain a new perspective of diagnosis and treatment of asthma patients, showing this relationship. The study was conducted on 60 asthmatic children and 40 healthy controls aged 5-18 years. The patient group was divided into two groups of allergic and nonallergic. Serum 25 hidroxy vitamin D levels were assesed, VDR genotypes were determined by PCR-RFLP method using endonuclease Apa1, Taq1 and Fok1, VDR mRNA levels were determined by Real Time PCR method. Vitamin D, VDR genotypes and VDR mRNA compared between the two groups and with each other. In relation to serum vitamin D levels, a significant difference was not observed between asthmatic patients and healthy childrens. We reported a significant association between VDR Taq1 polymorphisms and asthma. No significant differences was found in the distribution of genotypes and alleles frequencies between patients and controls for the Apa1 and Fok1 polymorphisms. No association was found between VDR SNPs and serum vitamin D levels. There was significantly increased expression of VDR mRNA in asthmatics compared to controls. Further studies with a larger sample of patients will improve our understanding of the contribution of this and other genes to asthma status and atopy and allow preventive and/or therapeutic interventions in asthmatic patients. Keywords: Asthma, vitamin D, VDR gene polymorphism.