A disintegrin and metalloproteinase 33 (ADAM33) gene polymorphism association with asthma in Egyptian children

Abstract

A disintegrin and metalloproteinase-encoding gene (ADAM33), was recently identified as an asthma susceptibility gene. ADAM33 protein is expressed in smooth muscle cells of bronchi and pulmonary fibroblasts, playing a major role in airway remodeling. Earlier studies, have mostly confirmed a link between ADAM33 and asthma as well as bronchial hyperresponsiveness. This work studied a group of Egyptian asthmatic children for 3 ADAM33 single nucleotide polymorphisms (SNPs), previously identified as putative risk alleles: T1 G >. A(rs2280091), T2 A >. G(rs2280090), V4 G >. C(rs2787094) using Polymerase Chain Reaction - restriction fragment length polymorphism (PCRRFLP) with emphasis on their relation to clinical (severity, smoking, family history, and atopic manifestations) and laboratory data (Ig Immunoglobulin E (Ig E) level and absolute eosinophilia) and pulmonary functions. Sixty (3-12. years old) asthmatic children and 32 matched controls were recruited. The genotype distribution for the SNPs showed no significant difference between the patients and the controls. A higher frequency of the (AA) genotype of T1 polymorphism was found in controls (75%) than in patients (41%), while the (AG) variant was higher in cases (46.6%) than in controls (21.9%) but with no statistically significant difference. Also the (GG) genotype was higher in cases (11.6%) than in controls (3.1%) but with no statistical significance. The allelic frequencies of T1 showed a higher (A) allele in controls (85.93%) than cases (65%) and higher (G) allele in cases (35%) than controls (14.06%), showing a high significant difference. No correlation was found between (T1, T2, and V4) and the demographic, clinical and laboratory parameters, except SNP T1 showing a positive correlation with Ig E level, and SNP V4 showing a positive correlation with passive smoking as a precipitating factor and borderline significance with absolute eosinophilia. In conclusion, no significant association was detected between these SNPs and asthma susceptibility in this study. © 2012.