Association of polymorphisms of two histamine-metabolizing enzymes with allergic asthma in Egyptian children

Background: Histamine released from mast cells and basophils plays a key role in the development of allergic diseases such as allergic asthma, rhinitis or anaphylaxis. Histamine-metabolizing enzymes: N-methyltransferase (HNMT) and amiloride binding protein 1(ABP) are involved in allergic inflammation.Objective: This study was undertaken to evaluate the relationship between polymorphisms of two genes encoding the histamine metabolizing enzymes HNMT and ABP1 with the development of allergic asthma in Egyptian children.Methods: This is a case control study performed on 100 atopic asthmatic and 94 healthy control children. Conventional method of PCR amplification was used for genotyping.Results: Distribution of HNMT -105 Thr → Ile (-314 C to T) single nucleotide polymorphism (SNP) genotypes and Thr and Ile (C and T) alleles among patients and controls revealed significant increase in the frequencies of Thr / Ile (CT) and Thr / Ile (CT) + Ile / Ile (TT) in atopic asthmatics than in controls (p= 0.04 and 0.002 respectively). There was also a significant increase in Ile (T) alleles in atopic asthmatic patients than controls (p= 0.002). The 2029 CG SNP polymorphism of ABP1gene was significantly associated with atopic asthma (p=0.0003).Conclusion: The results of this study suggest that genetic variations in the histaminemetabolizing enzyme (HNMT and ABP1) genes might contribute to the pathogenesis of asthma in the studied children.Keywords: Amiloride binding protein, asthma, atopy, children, Nmethyltransferas