India: The Last and Best Frontier for Cystic Fibrosis Newborn Screening with Perspectives on Special Challenges.

Because a delayed diagnosis of cystic fibrosis (CF) is detrimental and may be fatal, screening at birth has become routine in the Western world and has proven beneficial for many reasons, in addition to enabling prompt specialized care. Newborn screening (NBS) programs have elucidated the true incidence of CF in a variety of populations and enabled rapid genotype identification through the analysis of the cystic fibrosis transmembrane regulator (CFTR) gene. NBS studies also have revealed regional and population differences in CFTR variants and refuted the dogma that CF is a "white person's disease". But some regions have not yet implemented CF NBS, particularly in Asia where the disease prevalence has been uncertain. While the needs of a few low-and-middle-income countries are being addressed sequentially, one of the regions of greatest current interest is the Indian subcontinent because of recent data suggesting a higher incidence than that previously assumed, and clinical observations indicating tragic outcomes due to delayed diagnoses or failure to diagnose the disorder in young children. Thus, we conclude that the opportunities for research combined with service in the Indian subcontinent are urgent and potentially very impactful. Consequently, India is the last and best frontier for CF NBS, as we argue herein.