Background: Cystic fibrosis transmembrane conductance regulator (CFTR) is an asthma susceptibility gene. Individuals heterozygous for CFTR gene mutation may develop obstructive pulmonary disease like bronchial asthma.
Aim and objective: To find out the association of S549N and IVS8-5T variants of the CFTR gene with bronchial asthma and its severity and to assess the combinational effect of S549N and IVS8-5T variants on severity of disease.
Materials and methods: Included were 250 clinically diagnosed bronchial asthma cases aged 5 months to 15 years and 250 age- and sex-matched controls. All cases were further categorized into four different categories as per Global Initiative for Asthma criteria (GINA) guidelines: mild intermittent (83), mild persistent (96), moderate persistent (52), and severe persistent (19). Screening for S549N and 5T variants was done using the polymerase chain reaction-restriction fragment length polymorphism method.
Result: The proportion of IVS8-5T variant was found significantly higher in cases (10.8%) as compared with controls (2.4%) (p=0.001); however, no significant difference in the proportion of S549N was observed among cases (2.0%) and controls (0.8%) (p=0.447). Individuals mutant for IVS8-5T variant had increased risk for persistent asthma (p=0.000).
Discussion: We conclude that IVS8-5T variant is associated with bronchial asthma and can also increase severity of the disease.