• Journal of The Korean Society of Inherited Metabolic disease
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• v.16 no.1
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• pp.42-46
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• 2016

Isovaleric acidemia is autosomal-recessively inherited and an inborn error of metabolism caused by abnormal leucine metabolism due to the genetic defect of IVD (Isovaleryl-CoA dehydrogenase). IVD corresponds to mitochondrial matrix enzyme that acts on converting isovaleryl-CoA into 3-methylcrotonyl-CoA in the leucine catabolism. The IVD gene is located at Chromosome 15q14-q15, particularly between base pair 40,405,485 and base pair 40,435,948. It consists of 12 exons and has been reported to cause over 50 diseases so far. We conducted IVD gene test on the patient with acute isovaleric acidemia and confirmed a new type of mutation for the first time. As a result of analyzing the IVD gene sequence, we found out that c.129T>G(p.Asn43Lys) and c.1033A>G(p.Asn345Asp) mutations exist as heterozygosity at Exon 1 and Exon 10 respectively, novel mutation.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.16 no.2
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• pp.57-61
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• 2016

Isovaleric acidemia (IVA) is an autosomal recessively inherited organic acid disorder due to a defect of the enzyme isovaleryl-CoA dehydrogenase in the leucine metabolic pathway. Deficiency of this enzyme results in the accumulation of derivatives of isovaleryl-CoA. In acute illness in IVA, isovaleric acid and its derivatives accumulate and profound metabolic acidosis with ketosis, characteristic pungent body odor, hypoglycemia, and hyperammonemia can be developed. Additionally, recurrent vomiting, failure to thrive, developmental delay, epilepsy and mental retardation are chronic presenting symptoms and signs for IVA. On the result of newborn screening for inherited metabolic disorders, increased levels of isovalerylcarnitine (C5) are shown. However, C5 elevation can be accompanied with short/branched-chain acyl-CoA dehydrogenase (SBCAD) and therapy with certain antibiotics containing pivalic acid. Quantitative measurement of organic acids in urine and acylcarnitine profiles in plasma are necessary to differential diagnosis. Molecular genetic analysis of the IVD gene for IVA and ACADSB is also helpful to confirm IVA and SBCAD deficiency, respectively. Considering that IVA can be associated with significant morbidity and mortality at acute presentation of metabolic crisis, early diagnosis prior to the onset of symptoms by newborn screening enable to introduction of early treatment and prevention of acute and chronic complications.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.2 no.1
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• pp.7-11
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• 2002

Isovaleric acidemia is an inborn error in metabolism due to a defect in isovaleryl-CoA dehydrogenase. Accumulation of serum isovaleric acid causes poor feeding, vomiting, lethargy, hypothermia, convulsion, mental retardation, etc. It is inherited as an autosomal recessive trait. Since the first reports of isovaleric acidemia by Tanaka et al in 1966, more than 60 cases have been reported. There are two clinically different presentations of isovaleric acidemia, with about half the patients presenting with an acute severe neonatal form and about half with a chronic intermittent form. The difference in clinical presentation may not be a consequence of differing severities of the causative mutation, but a result of the timing of application of catabolic stress or the ability to form isovalerylglycine. We described here clinical and organic acid analytical findings of in 3 cases isovaleric acidemia.

• Clinical and Experimental Pediatrics
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• v.56 no.8
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• pp.351-354
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• 2013

Isovaleric aciduria (IVA) is caused by an autosomal recessive deficiency of isovaleryl-CoA dehydrogenase (IVD). IVA presents either in the neonatal period as an acute episode of fulminant metabolic acidosis, which may lead to coma or death, or later as a "chronic intermittent form" that is associated with developmental delays, with or without recurrent acidotic episodes during periods of stress, such as infections. Here, we report the case of a 2-year old boy with IVA who presented with the chronic intermittent form. He was admitted to Asan Medical Center Children's Hospital with recurrent vomiting. Metabolic acidosis, hyperammonemia, elevated serum lactate and isovalerylcarnitine levels, and markedly increased urine isovalerylglycine concentration were noted. Sequence analysis of the IVD gene in the patient revealed the novel compound mutations-a missense mutation, c.986T>C (p.Met329Thr) and a frameshift mutation, c.1083del (p.Ile361fs$^*11$). Following stabilization during the acute phase, the patient has remained in a stable condition on a low-leucine diet.