Identification of unique pattern of CFTR gene mutations in cystic fibrosis in an ethnic Kashmiri Population (North India)

Background: Cystic Fibrosis (CF) one of the most common severe autosomal recessive disorders is caused by mutations in CFTR gene. The mutation distributions vary widely between different geographical and ethnic groups. In view of ethnic nature of Kashmiri population (North India), we aim at looking for the 3 common mutations Δ508, 3849+10 kb, C>T and W1282X in CF suspected cases. Method: The mutations were evaluated in 150 highly suspected children with CF, proven by clinical features. ARMS-PCR was used for mutation detection of Δ508 and W1282X while as 3849+10 kb, C>T was assessed by indigenously developed ARMS-PCR and results were confirmed by RFLP. Results: Of the 150 suspected CF cases, one of the three mutations was found in 60 out of the 300 alleles genotyped. Δ508 mutation was found in 36 of 150 (24%) cases, 3849+10 kb, C>T in 24 of 150(16%) cases while as no mutation was observed in W1282X. Interestingly 08 of 09 samples with normal sweat chloride were detected positive for 3849+10 kb, C>T mutation. Conclusion: In this report, frequency of the Δ508 mutation in Kashmiri children with CF is less as compared to the Western Countries. Interestingly, we identified 3849+10 kb, C>T mutation as unique in population under study with much higher frequency as compared to rest of the world. Further we found intron 19, 3849+10 kb, C>T mutation serves as marker in those CF cases having sweat chloride negative.