Most cases of newly diagnosed diabetes mellitus occurred in patients with adult-onset MPHD (13 patients; 7 were rhGH-naïve and 6 were pretreated); the remaining cases of new-onset diabetes mellitus occurred in a patient with childhood-onset MPHD who had previously received GH replacement therapy (n = 1), and a patient with adulthood-onset isolated GHD who was naïve to GH replacement therapy (n = 1). This evidence concerns the gene GH1 and diabetes mellitus.