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