Deficient Biotinidase Activity in Late-Onset Multiple Carboxylase Deficiency

Abstract

To the Editor: Two forms of multiple carboxylase deficiency are recognized that lead to kctoacidosis and organic acidemia beginning shortly after birth and in early infancy, respectively.^{1 , 2} Both forms are associated with diminished activity of the biotin-dependent carboxylases in the blood leukocytes of untreated patients, and both respond to the administration of pharmacologic doses of biotin. The neonatal form is a recessive trait that results from a defect in holocarboxylase synthetase, the enzyme that covalently links biotin to propionyl-CoA-carboxylase, pyruvate carboxylase, and β-methylcrotonyl-CoA carboxylase.³ High doses of the vitamin can lead to a complete remission of the presenting symptoms of . . .