Organic Acid Disorders

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Disease Name Isovaleric acidemia
Alternate name(s) Isovaleric acid CoA dehydrogenase deficiency
Acronym IVA
Disease Classification Organic Acid Disorder
Variants Yes
Variant name Chronic intermittent form
Symptom onset Infancy (in the acute neonatal form). The chronic intermittent form presents later in infancy or in childhood.
Symptoms Episodic overwhelming illness with vomiting, ketosis, acidosis and coma. Hematological abnormalities include leucopenia, thrombocytopenia and possible anemia.
Natural history without treatment About 50% of patients with the acute neonatal form will die during their first episode. Survivors may have neurological damage though several have made complete recoveries. Patients with the chronic form may have neurologic damage, but the majority of patients are developmentally normal.
Natural history with treatment Intellectual prognosis depends on early diagnosis and treatment and subsequently on long-term compliance. If treated appropriately, most will have normal development.
Treatment Low protein diet with restricted leucine intake, glycine supplementation and possible carnitine supplementation.
Other Sometimes a “sweaty feet” odor is reported during an acute crisis.
Physical phenotype No obvious dysmorphic features.
Inheritance Autosomal recessive
General population incidence 1:230,000
Ethnic differences None known
Population N/A
Ethnic incidence N/A
Enzyme location N/A
Enzyme Function Isovaleryl-CoA dehydrogenase is the first step in the branched chain organic acid metabolism of leucine.
Missing Enzyme Isovaleryl-CoA dehydrogenase
Metabolite changes Urinary isovaleryl glycine, 3-hydroxysoraline acid, increased isovaleric acid in blood. During acute attacks, 4-hydroxyisovaleric acid, mesaconic acid, and methylsuccinic acid, isovalerylglycine and 3-hydroxyisovaleric acid are present.
Gene IVD
Gene location 15q14-15
DNA testing available No
DNA testing detail N/A
Prenatal testing Enzyme analysis by GCMS in amniotic fluid or CVS tissue.
MS/MS Profile Elevated C5 isovaleryl carnitine
OMIM Link www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=243500
Genetests Link www.genetests.org
Support Group

Organic Acidemia Association
www.oaanews.org

Save Babies through Screening Foundation
www.savebabies.org

Genetic Alliance
www.geneticalliance.org

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