Isovaleric acidemia
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Isovaleric acidemia | |
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Other names | Isovaleric aciduria, Isovaleric acid CoA dehydrogenase deficiency Isovaleric acid |
Specialty | Endocrinology |
Isovaleric acidemia is a rare
Symptoms and signs
A characteristic feature of isovaleric acidemia is a distinctive
In about half of cases, the signs and symptoms of this disorder become apparent within a few days after birth and include poor feeding, vomiting, seizures, and lack of energy that can progress to coma. These medical problems are typically severe and can be life-threatening. In the other half of cases, the signs and symptoms of the disorder appear during childhood and may come and go over time. They are often triggered by an infection.[citation needed]
Genetics
The disorder has an autosomal recessive inheritance pattern, which means the defective
Mutations in both copies of the IVD gene result in isovaleric acidemia.[citation needed]
Pathophysiology
The enzyme encoded by IVD,
Diagnosis
The urine of newborns can be screened for isovaleric acidemia using mass spectrometry,[3] allowing for early diagnosis. Elevations of isovalerylglycine in urine and of isovalerylcarnitine in plasma are found.
Screening
On 9 May 2014, the UK National Screening Committee (UK NSC) announced its recommendation to screen every newborn baby in the UK for four further genetic disorders as part of its NHS Newborn Blood Spot Screening programme, including isovaleric acidemia.[6]
Treatment
Treatment consists of dietary protein restriction, particularly leucine. During acute episodes, glycine is sometimes given, which conjugates with isovalerate forming isovalerylglycine, or carnitine which has a similar effect.
Elevated
Prognosis
A 2011 review of 176 cases found that diagnoses made early in life (within a few days of birth) were associated with more severe disease and a mortality of 33%. Children diagnosed later, and who had milder symptoms, showed a lower mortality rate of ~3%.[9]
Epidemiology
Isovaleric acidemia is estimated to affect at least 1 in 250,000 births in the United States.[10]
See also
References
- ^ Online Mendelian Inheritance in Man (OMIM): 243500
- PMID 17576084.
- ^ S2CID 19710669.
- PMID 9673537.
- ^ "Isovaleric Acidemia". National Organization for Rare Disorders.
- ^ "New screening will protect babies from death and disability". screening.nhs.uk. Archived from the original on 2015-06-10.
- ^ "The Online Metabolic and Molecular Bases of Inherited Disease: Home". Archived from the original on 2008-12-09.
- ^ "Genova Diagnostics (GDX) - Diagnostic Laboratory Testing for Wellness & Preventive Medicine". metametrix.com. Archived from the original on 2013-10-19. Retrieved 2011-06-06.
- PMID 22277694.
- ^ "Isovaleric acidemia". Genetics Home Reference. 4 May 2015.
External links
- Isovaleric acidemia at NLMGenetics Home Reference
- GeneReviews: The Organic Acidemias