Systemic Primary Carnitine Deficiency
Systemic primary carnitine deficiency is caused by a deficiency of carnitine, which is the compound responsible for the transport of fatty acids into the mitochondrial matrix. A lack of carnitine therefore leads to the build-up of fatty acids and fatty acyl-CoA, which can be toxic to cells. During periods of fasting, the body relies on hepatic glycogen stores for about the first 24 hours. After this, fat will be mobilized to the liver, where it will undergo beta-oxidation and subsequent conversion into ketone bodies. In patients with systemic primary carnitine deficiency however, the fat cannot be broken down, so ketone bodies cannot be formed. This leads to the finding of hypoketotic hypoglycemia, which is essentially just a hypoglycemic state that is NOT accompanied by ketogenesis. MCAD is a similar disease that hits a different step in this same pathway, so it may also present with hypoketotic hypoglycemia.