Carnitine-acylcarnitine translocase (CACT) deficiency

About the condition	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.
Inheritance	Autosomal recessive
Year screening started in WA	2005
Incidence in Australia	Currently unknown
Gene defect	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.
Symptoms if untreated	Hypoketotic hypoglycaemia Hyperammonaemia Cardiomyopathy, arrhythmia Skeletal myopathy Hepatomegaly Coma and death
Metabolites on bloodspot screening	Increased long-chain acylcarnitines (C16 and C18:1) Increased (C16+C18:1)/C2 ratio
Diagnostic tests	Plasma acylcarnitine profile Urine organic acids SLC25A20 gene analysis
Treatment	High-carbohydrate, low-fat diet Restriction of long-chain fatty acids Carnitine supplementation Cornstarch supplementation Avoidance of fasting IV glucose during illness
Screening issues	Efficacy of treatment unknown; disease is usually fatal Children with residual protein activity may have a better outcome