First report of type 2 diabetes mellitus in an adult with 3-hydroxy-3-methylglutaryl coenzyme A lyase deficiency.

In a patient with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) lyase deficiency and type 2 diabetes mellitus (T2DM), management principles include avoiding hypoglycemia to prevent metabolic decompensation, providing insulin for proper glucose utilization, and moderation of carbohydrate intake to prevent consequences of chronic hyperglycemia. The development of insulin resistance in the form of T2DM in HMG-CoA lyase deficiency likely triggered a state similar to hypoglycemia, leading to cellular energy deficiency and subsequently metabolic decompensation. It is important to avoid hypoglycemia in patients with HMG-CoA lyase deficiency and T2DM, as the risk of metabolic decompensation is increased due to the lack of ketogenesis in HMG-CoA lyase deficiency. Selection of antidiabetic agents in this patient population requires careful consideration, and agents that have a higher risk of hypoglycemia should be avoided.