HYPERVALINEMIA A Defect in Valine Transamination

The metabolism of the peripheral leucocyte has been studied in a child presenting with mental retardation and hypervalinemia. A defect in the transamination of valine was demonstrated. Evidence is presented that the transamination of value is dependent on an enzyme that is specific for valine. Transamination of valine is demonstrable in placenta, suggesting the possibility that the diagnosis may be made before birth.