Loving Kiss From A Big Brother

Child and Adolescent Health Service

Services A – Z


Princess Margaret Hospital

WA Newborn Screening Program

Disorder: Multiple carboxylase deficiency (MCD)

Alternative names: Holocarboxylase synthetase (HCS) deficiency

Diagnostic metabolites on MSMS
  • Increased C5OH acylcarnitines
Enzyme defect
  • Deficiency of holocarboxylase synthetase, the enzyme that covalently links biotin to propionyl-CoA carboxylase, pyruvate carboxylase, and 3-methylcrotonyl-CoA carboxylase
  • Autosomal recessive
Incidence in Australia
  • Currently unknown
Diagnostic tests
  • Plasma carnitine
  • Plasma acylcarnitine profile
  • Plasma amino acids
  • Urine organic acids
Symptoms if untreated
  • Metabolic ketolactic acidosis
  • Vomiting, lethargy
  • Seizures, hypotonia
  • Skin rashes, hair loss
  • Hearing loss, optic atrophy
  • Recurrent infections
  • Mental retardation
  • Coma and death possible
  • Later-onset forms occur
  • Biotin supplementation
Screening issues  
Additional information

To Top

All contents copyright Government of Western Australia. All rights reserved