DEFINITION

• Cystic fibrosis (CF): an autosomal recessive disease, diagnosed if : (1) clinical symptoms consistent with CF in at least one organ system AND (2) evidence of CF transmembrane conductance regulator (CFTR) dysfunction, which can include elevated sweat chloride >60 mmol/L on 2 occasions, presence of one of two disease-causing mutations in the CFTR (most common mutation is delta F508), or abnormal nasal potential difference.
• Clinical manifestations: respiratory tract disease, sinus disease, exocrine pancreatic insufficiency, diabetes, meconium ileus and distal ileal obstruction, biliary disease, infertility, musculoskeletal disorders (reduced bone mineral content, hypertrophic osteoarthropathy), nephrolithiasis and nephrocalcinosis, and recurrent venous thrombosis.
• Cystic fibrosis-related diabetes (CFRD): distinct from types 1 or 2 diabetes, with evidence of beta cell dysfunction but conflicting evidence regarding insulin resistance. Because basal insulin secretion is retained, patients with CFRD are not ketosis prone.