Diagnosis of a patient with a kinetic variant of medium and short-chain 3-hydroxyacyl-CoA dehydrogenase deficiency by newborn screening.

Medium and short-chain 3-hydroxyacyl-CoA dehydrogenase deficiency is a rare cause of impaired mitochondrial fatty acid oxidation. We present a case report of a patient with hyperinsulinism and homozygosity for a novel mutation causing a kinetic variant of the enzyme. The diagnosis was initially inferred by abnormal newborn screening acylcarnitine analysis with elevated C4-hydroxyacylcarnitine.