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

Abstract

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, Nmethyltransferase