Photo Credit: Dr. Microbe

Developing mild, but not severe, asthma was more likely in patients with the T allele and CT genotype in the co-dominant genetic model and the (CT+TT) genotype in the recessive model, according to a study published in the Journal of Asthma and Allergy. Researchers also observed a higher incidence of severe asthma in elderly females with associated nasal polyps and a history of childhood-onset disease. The investigation included 126 healthy controls and 215 patients with asthma, of which 102 had mild asthma. To identify various IL-4 (C590T) gene polymorphism genotypes, the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used. Compared with controls, the study team found that the T allele frequency was higher in mild asthma (P=0.002) but not in severe asthma (P=0.12). The CT genotype and (CT+TT vs CC) increased the probability of asthma three-fold (P<0.001, 0.001) in patients with mild asthma. No significant link with severe asthma was observed in either genetic model.