Islets from CFRD patients have decreased insulin staining compared to age matchedcontrols without CFRD, with a concomitant increase in glucagon staining (Figure 1).9 However, there is variability in β-cell mass in post-mortem studies on CF patients.4 Prolonged hyperglycemia has been attributed as the cause of reducedβ-cell mass as changes in β-cell mass are reversible when blood glucose levelsare normalized.37 As mentioned, CF patients in general have an abnormal glucose metabolism.19 This evidence concerns the gene GCG and cystic fibrosis-related diabetes.