Biochemistry Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt.
Hum Immunol. 2013 Dec;74(12):1659-64. doi: 10.1016/j.humimm.2013.08.284. Epub 2013 Sep 2.
Asthma is a genetically heterogeneous disease. Genetic variants in vitamin D pathway have been reported to be involved with asthma risk. The study aimed to test whether vitamin D binding protein (VDBP or GC-group component) and vitamin D receptor (VDR) gene polymorphisms were associated with asthma characteristics as well as vitamin D level in Egyptian children.
The study included 51 asthmatic children and 33 healthy controls of matched sex and age. All participants were genotyped for two SNPs; GC (rs2282679) and VDR (rs2228570) using TaqMan allele discrimination assays.
Genotype distribution of GC and VDR showed a significant association with asthma (P = 0.02, P = 0.002). Children carrying the risk "G" allele for GC SNP are 2.22 times more prone to develop asthma [OR = 2.22, 95% CI (1.18-4.2)] whereas those carrying the risk "F" allele for VDR SNP are nearly twice and half times susceptible for asthma development [OR = 2.68, 95% CI (1.36-5.28)] than healthy individuals. For the GC SNP, homozygous children "GG" exhibited significant difference in pulmonary functions (FEV1, FEV1/FVC), asthma severity and asthma control, IgE and vitamin D levels compared to pooled cases of GT and TT genotypes. For the VDR SNP, no significant association between VDR variants and the tested characteristics except for the pulmonary functions where the FEV1/FVC in asthmatic children with "FF " genotype differ significantly from those carrying "Ff"genotype.
GC and VDR variants may be implicated in asthma susceptibility; hence, further larger studies are still needed to extrapolate our findings to the general population.
哮喘是一种遗传异质性疾病。维生素 D 通路中的遗传变异已被报道与哮喘风险有关。本研究旨在测试维生素 D 结合蛋白（VDBP 或 GC 组成分）和维生素 D 受体（VDR）基因多态性是否与埃及儿童的哮喘特征以及维生素 D 水平有关。
该研究包括 51 例哮喘患儿和 33 例性别和年龄匹配的健康对照者。所有参与者均采用 TaqMan 等位基因鉴别检测法对两个 SNP（GC(rs2282679)和 VDR(rs2228570)进行基因分型。
GC 和 VDR 的基因型分布与哮喘有显著相关性（P=0.02，P=0.002）。携带 GC SNP 风险“G”等位基因的儿童患哮喘的风险增加 2.22 倍[OR=2.22，95%CI(1.18-4.2)]，而携带 VDR SNP 风险“F”等位基因的儿童患哮喘的风险增加近 2 倍，减少 50%[OR=2.68，95%CI(1.36-5.28)]。对于 GC SNP，纯合子儿童“GG”在肺功能（FEV1、FEV1/FVC）、哮喘严重程度和哮喘控制、IgE 和维生素 D 水平方面与 GT 和 TT 基因型的混合病例有显著差异。对于 VDR SNP，除了肺功能外，VDR 变异与所测试的特征之间没有显著关联，在哮喘患儿中，携带“FF”基因型的 FEV1/FVC 与携带“Ff”基因型的患儿有显著差异。
GC 和 VDR 变异可能与哮喘易感性有关；因此，需要进一步进行更大规模的研究，将我们的发现推广到一般人群。
