Beta-ketothiolase (BKT) deficiency
Beta-ketothiolase (BKT) deficiency
Alternative names
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- alpha-methylacetoacetic aciduria
- 3-ketothiolase deficiency
- Mitochondrial acetoacetyl-CoA thiolase deficiency
- T2 deficiency
- 3-oxothiolase deficiency
- 2-methyl-3-hydroxybutyric acidaemia
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About the condition
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BKT deficiency is an organic acid disorder. It is a hereditary disease that is caused by a missing enzyme needed to convert protein into energy. There is also failure to utilise ketone bodies.
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Inheritance
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Autosomal recessive
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Year screening started in WA
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2005 |
Incidence in Australia
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Currently unknown
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Enzyme defect
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Deficiency of 3-ketothiolase, which converts 2-methylacetoacetyl-CoA to propionyl-CoA and acetyl-CoA.
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Symptoms if untreated
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- Episodic ketoacidosis
- Nausea and vomiting
- Intellectual disability
- Coma and death possible
- Significant clinical heterogeneity
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Metabolites on bloodspot screening
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Increased 2-methyl-3-hydroxybutyrylcarnitine and tiglylcarnitine (C5OH and C5:1).
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Diagnostic tests
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- Plasma acylcarnitine profile
- Urine organic acids
- ACAT1 gene analysis
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Treatment
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- Low-protein diet
- Carnitine supplementation
- Avoidance of fasting
- IV glucose and bicarbonate during crisis episodes
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Screening issues
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Not all cases will show biochemical abnormalities on newborn screening.
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