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.