CFTR and cystic fibrosis: These infants, labelled in the first months of life as CF transmembrane conductance regulator-related metabolic syndrome (CRMS)/CF screen–positive, inconclusive diagnosis (CFSPID) [7], remain healthy in most cases but may receive a CF diagnosis later due to a positive sweat test (ST) or a re-classification of CFTR variants as CF, possibly leading to the development of mild clinical CF features [8,9,10,11,12,13].