IGF1 and Leigh syndrome: Mice with targeted global disruption of the GHR gene (GHRKO mice) are excellent models of LS, presenting an obese, growth-retarded phenotype with low levels of IGF-1 and insulin, high levels of GH, and enhanced resistance to diabetes and cancer (2, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42).