The SLC9A3 gene encodes human NHE3, and SLC9A3 homozygous or compound heterozygous disease‐causing mutations have recently been reported in 9 patients from 8 families with congenital secretory sodium diarrhoea (MIM#616868).60, 61 Variants in the SLC9A3 gene influence susceptibility to bacterial infections and severity of lung disease by interacting with the CFTR gene, providing evidence for a potential modulatory effect in Cystic Fibrosis.62, 63 No association has been found to date between SLC9A3 variants and renal proximal tubulopathies. Here, SLC9A3 is linked to cystic fibrosis.