Function, pharmacological correction and maturation of new Indian CFTR gene mutations

Cystic fibrosis (CF) is rare in India. Most CF mutations identified are not yet functionally characterized. Hence, genetic counseling and adoption of therapeutic approach are particularly difficult. Our aim was to study the function and maturation of a spectrum of eleven Indian CFTR mutations from classical CF and infertile male patients with CBAVD.

We used Western blot, pharmacology and iodide efflux to study CFTR maturation and chloride transport in BHK cells expressing pEGFP-CFTR constructs for L69H, F87I, S118P, G126S, H139Q, F157C, F494L, E543A, S549N, Y852F and D1270E.

Among these CFTR mutants, only L69H is not processed as a c-band and not functional at 37°C. However, the functions of L69H and S549N and the maturation of L69H are corrected at 27°C and by the investigational drug VX809.

These data should help in developing counseling and therapeutic approaches in India. We identified L69H as a novel class II CF mutation.