Abbreviations: CFTR: Cystic Fibrosis transmembrane conductance regulator; FEV₁: forced expiratory volume in the 1st second; SC: sweat chloride; HA: Hypochloremic Alkalosis; CBAVD: congenital bilateral absence of the vas deferens; Pa: Pseudomonas aeruginosa ; CRMS/CFSPID: cystic fibrosis transmembrane conductance regulator-related metabolic syndrome/cystic fibrosis screen positive, inconclusive diagnosis; CF: Cystic Fibrosis; CFTR-RD: CFTR-related disorder.

Conflict of Interest: The Auhtors declare no conflicts of interest

Tosco A¹,

Carnovale V²,

Claut L³,

Fabrizzi B⁴,

Majo F⁵,

Castellani C⁶,

Sepe A¹,

Castaldo G⁷,

Terlizzi V⁸

¹Paediatric Unit, Department of Translational Medical Sciences, Cystic Fibrosis Regional Reference Center, University of Naples Federico II, Naples, Italy;

² Department of Translational Medical Science, Cystic Fibrosis Center, Adult Unit, University of Naples ”Federico II”, Italy;

³ Cystic Fibrosis Regional Reference Center, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, University of Milan, Department of Pathophysiology and Transplantation, Milan, Italy;

⁴ Cystic Fibrosis Regional Reference Center, Mother - Child Department, United Hospitals, Ancona, Italy;

⁵ Cystic Fibrosis Centre, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy;

⁶ IRCCS Istituto Giannina Gaslini, Genova, Italy;

⁷ Department of Molecular Medicine and Medical Biotechnology, University of Naples, Naples, Italy; CEINGE-Advanced Biotechnology, Naples, Italy;

⁸ Meyer Children’s Hospital, Cystic Fibrosis Regional Reference Center, Department of Paediatric Medicine, Florence, Italy.