Isovaleric Acidemia

Isovaleric acidemia (IVA) is an inborn error of leucine metabolism. The acute neonatal phenotype usually presents within the first 2 weeks of life with poor feeding, vomiting, decreased levels of consciousness, seizures, acidosis and hyperammonemia. A characteristic smell of “sweaty socks” may also be present during an acute illness. A chronic intermittent presentation may occur that is characterized by recurrent episodes of ketoacidosis, vomiting, lethargy, coma and varying degrees of developmental delay. Patients who survive the acute neonatal presentation have a similar clinical course as those with the chronic phenotype. Since the inception of MS/MS based newborn screening, a group of potentially asymptomatic patients has emerged with a mild biochemical phenotype.

Tests Available

Forms and Documents

Test Details

  • Confirmation of biochemical diagnosis
  • Carrier testing
  • Prenatal diagnosis in at risk pregnancies


4-5 weeks
2-5 mL Blood - Lavender Top Tube
Buccal Swabs

*Reporting times are typical, but could be extended in situations outside GeneDx's reasonable control.


  • 796.6 Abnormal findings on neonatal screening
  • 276.2 Acidosis Acidosis
  • 270.3 Disturbances of branched-chain amino-acid metabolism, Disturbances of metabolism of leucine, isoleucine, and valine, Hypervalinemia Intermittent branched-chain ketonuria, Leucine-induced hypoglycemia, Leucinosis, Maple syrup urine disease
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**The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.


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  2. Vockley J. et al., (2000) Am J Hum Genet 66 :356-367
  3. Lin, WD et al., (2007) Mol Genet Metab 90 :134-139
  4. Lee, YW et al., (2007) Mol Genet Metab 92 :71-77
  5. Vockley, J and Ensenauer R. (2006) Am J Med Genet C Semin Med Genet 142:95-103