Carnitine-acylcarnitine translocase (CACT) deficiency
Carnitine-acylcarnitine translocase (CACT) deficiency
About the condition
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CACT deficiency is a long-chain fatty acid oxidation disorder. It is a hereditary disease that is caused by a missing protein needed to convert fat into energy. It is a severe disorder associated with cardiomyopathy, arrhythmias, and liver disease and is invariably fatal in the first year of life.
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Inheritance
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Autosomal recessive
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Year screening started in WA |
2005 |
Incidence in Australia
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Currently unknown
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Gene defect
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Caused by defects in the SLC25A20 gene, which encodes a mitochondrial-membrane carrier protein that shuttles acylcarnitine substrates between the cytosol and the intramitochondrial matrix.
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Symptoms if untreated
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- Hypoketotic hypoglycaemia
- Hyperammonaemia
- Cardiomyopathy, arrhythmia
- Skeletal myopathy
- Hepatomegaly
- Coma and death
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Metabolites on bloodspot screening
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- Increased long-chain acylcarnitines (C16 and C18:1)
- Increased (C16+C18:1)/C2 ratio
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Diagnostic tests
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- Plasma acylcarnitine profile
- Urine organic acids
- SLC25A20 gene analysis
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Treatment
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- High-carbohydrate, low-fat diet
- Restriction of long-chain fatty acids
- Carnitine supplementation
- Cornstarch supplementation
- Avoidance of fasting
- IV glucose during illness
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Screening issues
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- Efficacy of treatment unknown; disease is usually fatal
- Children with residual protein activity may have a better outcome
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