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Review
. 2006 May 15;142C(2):95-103.
doi: 10.1002/ajmg.c.30089.

Isovaleric acidemia: new aspects of genetic and phenotypic heterogeneity

Jerry Vockley  1 , Regina Ensenauer
Affiliations
Review

Isovaleric acidemia: new aspects of genetic and phenotypic heterogeneity

Jerry Vockley et al. Am J Med Genet C Semin Med Genet. .

Abstract

Isovaleric acidemia (IVA) is an autosomal recessive inborn error of leucine metabolism caused by a deficiency of the mitochondrial enzyme isovaleryl-CoA dehydrogenase (IVD) resulting in the accumulation of derivatives of isovaleryl-CoA. It was the first organic acidemia recognized in humans and can cause significant morbidity and mortality. Early diagnosis and treatment with a protein restricted diet and supplementation with carnitine and glycine are effective in promoting normal development in severely affected individuals. Both intra- and interfamilial variability have been recognized. Initially, two phenotypes with either an acute neonatal or a chronic intermittent presentation were described. More recently, a third group of individuals with mild biochemical abnormalities who can be asymptomatic have been identified through newborn screening of blood spots by tandem mass spectrometry. IVD is a flavoenzyme that catalyzes the conversion of isovaleryl-CoA to 3-methylcrotonyl-CoA and transfers electrons to the electron transfer flavoprotein. Human IVD has been purified from tissue and recombinant sources and its biochemical and physical properties have been extensively studied. Molecular analysis of the IVD gene from patients with IVA has allowed characterization of different types of mutations in this gene. One missense mutation, 932C>T (A282V), is particularly common in patients identified through newborn screening with mild metabolite elevations and who have remained asymptomatic to date. This mutation leads to a partially active enzyme with altered catalytic properties; however, its effects on clinical outcome and the necessity of therapy are still unknown. A better understanding of the heterogeneity of this disease and the relevance of genotype/phenotype correlations to clinical management of patients are among the challenges remaining in the study of this disorder in the coming years.

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Figures

Figure 1
Figure 1
The catabolic pathway of leucine. Isovaleryl-CoA dehydrogenase catalyzes the conversion of isovaleryl-CoA to 3-methylcrotonyl-CoA. Enzyme deficiency results in the accumulation of isovaleryl-CoA derivatives.
Figure 2
Figure 2
Molecular defects in the IVD gene on chromosome 15q14–15 [Mohsen et al., 1998; Ensenauer et al., 2004]. The nucleotide change 932C>T (A282V) in exon 9 has been identified in a significant proportion of individuals diagnosed by newborn screening [Ensenauer et al., 2004].
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References

    1. Abdenur JE, Chamoles NA, Guinle AE, Schenone AB, Fuertes AN. Diagnosis of isovaleric acidaemia by tandem mass spectrometry: false positive result due to pivaloylcarnitine in a newborn screening programme. J Inherit Metab Dis. 1998;21:624–630. - PubMed
    1. Andresen B, Christensen E, Corydon T, Bross P, Pilgaard B, Wanders R, Ruiter J, Simonsen H, Winter V, Knudsen I, Schroeder LD, Gregersen N, Skovby F. Isolated 2-methylbutyrylglycinuria caused short/branched-chain acyl-CoA dehydrogenase deficiency: Identification of a new enzyme defect, resolution of its molecular basis, and evidence for distinct acyl-CoA dehydrogenases in isoleucine and valine metabolism. Am J Hum Gen. 2000;67:1095–1103. - PMC - PubMed
    1. Arnold WC, Brewster M, Byrne WJ, Booth B. Fanconi syndrome in a patient with a variant of isovaleric acidemia. Intl J Pediatr Nephr. 1986;7:95–98. - PubMed
    1. Attia N, Sakati N, al Ashwal A, al Saif R, Rashed M, Ozand PT. Isovaleric academia appearing as diabetic ketoacidosis. J Inherited Metab Disease. 1996;19:85–86. - PubMed
    1. Berry GT, Yudkoff M, Segal S. Isovaleric acidemia: medical and neurodevelopmental effects of long-term therapy. J Pediatr. 1988;113:58–64. - PubMed

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