Spectrum and distribution of CFTR gene mutations in asthma and chronic pancreatitis cases of North Indian population.

ABSTRACT

BACKGROUND: Cystic fibrosis transmembrane conductance regulator (CFTR) gene accounts for an autosomal recessive condition called cystic fibrosis (CF). In the Indian subcontinent, CF and its related diseases are under-diagnosed by the medical community due to poor knowledge of the disease and its confounding diagnosis, and also due to poor medical facilities available for these patients, thus causing an increased infant mortality rate with a low life expectancy in general. The aim of the study was to document the spectrum and distribution of CFTR mutations in controls, asthma and chronic pancreatitis cases of North India. METHODS: A total of 800 subjects including 400 controls, 250 asthma cases and150 chronic pancreatitis cases were analyzed for 6 mutations (F508del, G542X, G551D, R117H, W1282X, and S549N) and IVS8 Tn polymorphism. RESULTS: Out of 800 subjects, 18% [asthma - 24% (n=250), CP - 29.33% (n=150) cases and controls - 9.3% (n=400)] were positive for heterozygous mutation, 0.8% of the (n=250) asthmatic cases (n=250) were homozygous for IVS8 T5 polymorphism while no subjects were found positive for W1282X mutation. T5 polymorphism was more common in asthmatic cases while F508del mutation in chronic pancreatitis cases. The carrier frequency of F508del, G542X, G551D, R117H, S549N and T5 was 0.015, 0.025, 0.02, 0.005, 0.005, and 0.022 respectively. The cumulative carrier frequency was 0.093. CONCLUSION: CFTR mutations were underestimated in Indian population. The present study will serve in establishment of genetic screening and prenatal setup for Indian population.