Effect of ARG1 Gene (rs2781666) Polymorphism on Plasma Arginase Activity and Bronchial Asthma Prevalence and Severity.

Abstract

Background: Bronchial asthma is a chronic inflammatory condition that affects the lungs and causes airway narrowing. Multiple genetic and environmental factors contribute to bronchial asthma. The complex interactions between these factors play a vital role in the susceptibility to and severity of asthma. Several genetic factors are associated with the prevalence and severity of bronchial asthma. Among these genes, ARG1 rs2781666 polymorphism has been found to be associated with bronchial asthma prevalence worldwide. Furthermore, increased serum arginase activity has been reported in patients with asthma, suggesting an association with bronchial asthma phenotypes.

Purpose: To determine the frequency of ARG1 rs2781666 polymorphism among Jordanians, we compared plasma arginase activity and ARG1 rs2781666 polymorphism in asthmatic patients and non-asthmatic volunteers, and analyzed the distribution of rs2781666 genotypes among asthma severity groups.

Patients and methods: Four hundred and twenty-four asthmatic and non-asthmatic Jordanian subjects visiting the Jordan University Hospital were genotyped for ARG1 rs2781666 polymorphism using the polymerase chain reaction-restriction fragment length polymorphism method and were examined for serum arginase activity using an arginase activity assay.

Results and conclusions: There was a significant association between ARG1 rs2781666 G/T polymorphism and bronchial asthma frequency and severity. The GT genotype and T allele frequencies were significantly higher in asthmatic patients than in non-asthmatic patients. In addition, comparison between the ARG1 rs2781666 genotype distribution and asthma severity revealed that the TT genotype was more frequent in the severe asthma group. Furthermore, a comparison of plasma arginase activity between the asthmatic and non-asthmatic groups revealed that arginase activity was significantly higher in asthmatic patients than in non-asthmatic patients. In addition, the results showed a positive association between elevated plasma arginase activity and rs2781666 G/T in asthmatic patients compared to that in non-asthmatic subjects.