Associations of Matrix Metalloproteinase-7 Promoter Genotypes With Asthma Risk in Taiwan

Asthma is a complex chronic airway disease with multifactorial etiologies, including genetic predispositions. This study aimed to investigate the association between the MMP-7 promoter polymorphism -181A>G (rs11568818) and asthma susceptibility and severity in a Taiwanese population.

PCR-RFLP genotyping analysis was conducted on 198 patients with asthma and 453 healthy controls.

While no significant overall association was observed between genotypes and asthma risk [AG versus AA: odds ratio (OR)=1.31, 95% confidence interval (CI)=0.82-2.09, p=0.3117; GG versus AA: OR=2.42, 95%CI=0.69-8.46, p=0.2833], a borderline significance was found for the G allele (OR=1.44, 95%CI=0.96-2.15, p=0.0950). In age-stratified analysis, the AG genotype significantly increased asthma risk in individuals aged 25-40 years (OR=1.86, 95%CI=1.08-3.25, p=0.0365), but not in those over 40 years. Sex-stratified analyses revealed no significant associations in either males or females. Notably, genotype distribution correlated significantly with asthma severity (p for trend=0.0040). Individuals with AG and GG genotypes were more likely to present severe asthma symptoms compared to those with the AA genotype (AG: 24.7% vs. 11.2%, p=0.0144; GG: 5.5% vs. 0.8%, p=0.0418). The dominant model (AG+GG vs. AA) showed a higher prevalence in the severe group (30.2%) than in the milder group (12.0%), while the GG genotype conferred a high OR for severe disease (OR=7.19 vs. 3.16), approaching borderline significance.

MMP-7-181A>G is not a major susceptibility marker for asthma. However, the G allele may serve as a potential biomarker for younger-onset and more severe asthma phenotypes in Taiwanese individuals.