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Original Article


Association of Polymorphisms in the Mast Cell Chymase Gene Promoter Region (-1903 G/A) and
(TG)n(GA)m Repeat Downstream of the Gene With Bronchial Asthma in Children


EM Hossny,1 NH Amr,1 SB Elsayed,2 RA Nasr,2 EM Ibraheim1

1Department of Pediatrics, Ain Shams University, Cairo, Egypt
2Department of Microbiology and Immunology, Ain Shams University, Cairo, Egypt

J Investig Allergol Clin Immunol 2008; Vol. 18(5): 376-381



Background: Mast cell chymase is a mediator of inflammation and remodeling in the asthmatic lung. Although various studies have examined the association between the -1903 G/A single nucleotide polymorphism (SNP) in the mast cell chymase gene (CMA1) and allergic phenotypes, the results have been inconsistent. A (TG)n(GA)m repeat polymorphism 254 base pairs downstream of CMA1 has been reported in adult
asthmatics. We investigated the relationship between these CMA1 genetic variants and childhood asthma in Egyptian children.

Methods: A case-control study was undertaken in 15 children (6-10 years old) with bronchial asthma enrolled consecutively during exacerbation and 15 age-matched and sex-matched nonasthmatic control subjects. Genotyping was performed by polymerase chain reaction (PCR) restriction fragment length polymorphism to search for polymorphisms in the CMA1 gene promoter region (-1903 G/A) and PCR amplification followed by sequencing to detect the (TG)n(GA)m repeat 254 base pairs downstream of the gene.

Results: Our data showed a positive association between the CMA1 -1903 G/A SNP and asthma in children. The G allele was detected in 70% of patients while the A allele was more frequent in the controls (83.3%). Concerning the (TG)n(GA)m repeat, allele 39 was only present in asthmatics while allele 37 was more common in controls.

Conclusion: We report the association of the -1903 G/A CMA1 SNP and (TG)n(GA)m repeat polymorphism with bronchial asthma in a group of Egyptian children. These polymorphisms are possible determinants of asthma susceptibility and may be involved in regulating immunoglobulin E levels.

Key words: Alleles. Asthma. Children. Chymase gene. Immunoglobulin E. (TG)n(GA)m repeat polymorphism. Restriction fragment length polymorphism. Single nucleotide polymorphism.