The Global Increlex® Growth Forum Database (IGFD) Registry monitors real-world effectiveness and safety of recombinant human IGF-1 (rhIGF-1; Increlex® [mecasermin]) treatment in children and adolescents with severe growth failure due to severe primary IGF-I deficiency (SPIGFD). The gene discussed is IGF1; the disease is hyperinsulinemic hypoglycemia, familial, 4.