Association of Leukotriene C4 Synthase Gene Polymorphism with Clinical Response to Montelukast in Childhood Asthma

Shin, Kyung Sue; Kim, Youn Woo

Abstract

PURPOSE
Cysteinyl leukotrienes are important inflammatory mediators in the pathogenesis of asthma; therefore interruption of cysteinyl leukotrienes by leukotriene receptor antagonists improves clinical symptoms in the management of patients with mild to moderate asthma. We evaluated whether clinical response to montelukast, a leukotriene receptor antagonist, in childhood asthma was predicted by genotypes of leukotriene C4 synthase (LTC4S) promoter gene polymorphism. METHODS: An 8-week prospective, open trial of montelukast was carried out in 161 children with mild to moderate asthma. Genotyping of LTC4S gene polymorphism was determined by restriction fragment length polymorphism. RESULTS: The distribution of the LTC4S genotypes AA, AC, and CC was 70.8 percent, 23.6 percent, and 5.6 percent, respectively in asthma group and 74.0 percent, 22.6 percent, and 3.4 percent, respectively in control group. A statistically significant difference in the distribution of LTC4S genotype was not observed between the asthma and the control groups, and there was no significant difference between the LTC4S genotype and asthma severity. The responders to montelukast were significantly prevalent in the mild asthma group (P< 0.05). There was no significant difference in the distribution of the responders compared to non-responders within genotype in the total asthma group or the moderate asthma group. However, the responsiveness for montelukast was significant difference within genotype for both AA and AC/CC in the mild asthma group: The AA genotype was more included in the responder group (P< 0.05). CONCLUSION: In the mild persistent asthma group, the A allele of LTC4S polymorphism may be regarded as a predictable factor for clinical response to montelukast. However, LTC4S polymorphism was not significantly associated with the clinical response to montelukast in asthmatic children.