In long-term studies, feeding Rag1-/- mice a diet containing 45% kcal as fat for 28 weeks led to severe metabolic dysfunction relative to a control diet, including larger adipocyte size, intramyocellular lipid content, hepatic steatosis, insulin resistance, hyperinsulinemia, and impaired glucose tolerance [46]. The gene discussed is RAG1; the disease is Impaired glucose tolerance.