Isovaleric acidaemia (IVA)

Alternative name Isovaleryl-CoA dehydrogenase deficiency
About the condition IVA is an organic acid disorder. It is a hereditary disease that is caused by a missing enzyme needed to convert protein into energy.
Inheritance Autosomal recessive
Year screening started in WA
2005 
Incidence in Australia Currently unknown
Enzyme defect Deficiency of the enzyme isovaleryl-CoA dehydrogenase, which catalyses an early step in the metabolism of the branched-chain amino acid leucine.
Symptoms if untreated
  • Episodic ketoacidosis
  • Vomiting
  • Cytopaenia
  • Coma and death possible
  • ‘Sweaty feet’ odour
  • A chronic intermittent form presents later in childhood
Metabolites on bloodspot screening Increased isovalerylcarnitine (C5).
Diagnostic tests
  • Plasma acylcarnitine profile
  • Urine organic acids
  • IVD gene analysis
Treatment
  • Low-protein diet (leucine-restricted)
  • Carnitine supplementation
  • Glycine supplementation
Screening issues There are milder variants of uncertain clinical significance.