Association of CFTR gene mutation with bronchial asthma

BACKGROUND Asthma is a complex genetic disorder. Several genes have been found associated with asthma. The cystic fibrosis transmembrane conductance regulator (CFTR) gene is one of them. AIM To assess the association of CFTR gene mutation with asthma and its severity as per GINA guidelines. SUBJECTS AND METHODS This was a hospital-based case-control study. Excluded from cases and controls were those with clinically suspected cystic fibrosis or sweat chloride level>60 mmol/L or suffering from other respiratory diseases. Included were 200 cases and 180 controls, aged 5 months to 15 years. Screening was done for CFTR gene mutations; ΔF508, G542X, G551D, R117H and W1282X using the ARMS-PCR method. RESULTS ΔF508 was found in three (1.5%) cases and two (1.1%) controls (p = 0.739), G542X in nine (4.5%) cases and five (2.8%) controls (p = 0.374), R117H in one (0.5%) case and one (0.6%) control (p = 0.940) and G551D in twelve (6.0%) cases and two (1.1%) controls (p = 0.012). Individuals carrier for G551D mutation had increased risk for persistent asthma (p = 0.006). Percent predicted FEV1 (p = 0.014) and FVC (p = 0.028) were significantly lower among carriers as compared to non-carriers. CONCLUSION Significantly higher frequency of G551D mutation among asthma patients compared with controls suggests that this mutation may increase risk for the disease and also its severity.