The Diagnostic Complexities of Cystic Fibrosis: When to Think of It and What to Do?

Cystic fibrosis (CF) is one of the most common life-shortening hereditary disorders, caused by a defect in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. This defect causes multi-system disease, but primarily it affects the lungs and pancreas. Over 2000 CFTR gene variants have been identified; these can result in variable CFTR protein function and, consequently, a diverse clinical phenotype. CF is not only diagnosed in children but also in adults and is present in non-White populations. In adults, CF often presents with an atypical phenotype, usually due to residual CFTR protein function, which can be caused by rare CFTR variants. As a result, diagnosing CF in adults can be challenging. In this review, we discuss who should be considered for CF, how and where the diagnosis is made, and why a timely CF diagnosis is important for all patients, as well as their families.