Neuroimage findings in 2-methyl-3-hydroxybutyryl-CoA dehydrogenase deficiency.

A case of 2-methyl-3-hydroxybutyryl-coenzyme A dehydrogenase deficiency, an X-linked defect of isoleucine degradation, is reported. A 10-month-old male infant with developmental regression, visual impairment, movement disorder, and seizures, he suffered acute deterioration with multiorganic failure after a respiratory infection. Laboratory studies revealed hyperlactacidemia and increased excretion of 2-methyl-3-hydroxybutyric acid (2M3HBA) and tiglylglycine (TG). The diagnosis was established by molecular genetic analysis of the involved X-chromosome gene HADH2. The patient was hemizygous for the mutation R130C (c. 388C>T). Magnetic resonance imaging disclosed frontotemporal atrophy and bilateral signal abnormalities in the putamina. The presence of basal ganglia abnormalities and lactic acidemia, also shared by mitochondrial disorders, suggests a common pathophysiologic mechanism of damage.