CFTR and cystic fibrosis: As of today, CF diagnosis remains challenging due to: (i) the high number of mutations and phenotypes [3,4,5], (ii) the struggle with the differential diagnosis in a small fraction (1–2%) of equivocal cases (e.g., between CF and CFTR-Related Metabolic Syndrome/CF Screen Positive, Inconclusive Diagnosis (CRMS/CFSPID) cases), but also in regard to (iii) the worldwide implementation of currently available newborn screening strategies and diagnosis tests [6].