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Test ID: CACTS    
Carnitine-Acylcarnitine Translocase Deficiency, Full Gene Analysis

Useful For Suggests clinical disorders or settings where the test may be helpful

Confirmation of diagnosis of carnitine-acylcarnitine translocase (CACT) deficiency


Carrier screening in cases where there is a family history of CACT deficiency, but disease-causing mutations have not been identified in an affected individual

Genetics Test Information Provides information that may help with selection of the correct test or proper submission of the test request


Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Carnitine-acylcarnitine translocase (CACT) deficiency is a rare autosomal recessive disorder of fatty acid oxidation. The disease typically presents in the neonatal period with severe hypoketotic hypoglycemia, hyperammonemia, cardiac abnormalities, hepatic dysfunction, skeletal muscle weakness, encephalopathy, and early death. However, presentations at a later age with a milder phenotype have also been reported.

Initial screening can be done with plasma acylcarnitines. Definitive diagnosis can be made by detection of reduced CACT enzyme activity. Mutations in the SLC25A20 gene are responsible for CACT deficiency, and sequencing of this gene is recommended after positive biochemical analysis.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

A small percentage of individuals who are carriers or have a diagnosis of carnitine-acylcarnitine translocase (CACT) deficiency may have a mutation that is not identified by this method (eg, promoter and deep intronic mutations). The absence of a mutation, therefore, does not eliminate the possibility of positive carrier status or the diagnosis of CACT deficiency.


In some cases, DNA alterations of undetermined significance may be identified.


Rare polymorphisms exist that could lead to false-negative or false-positive results. If results obtained do not match the clinical and biochemical findings, additional testing should be considered.


A previous bone marrow transplant from an allogenic donor will interfere with testing. Call Mayo Medical Laboratories for instructions for testing patients who have received a bone marrow transplant. 


Test results should be interpreted in the context of clinical findings, family history, and other laboratory data. Errors in our interpretation of results may occur if information given is inaccurate or incomplete.

Clinical Reference Provides recommendations for further in-depth reading of a clinical nature

1. Wang GL, Wang J, Douglas G, et al: Expanded molecular features of carnitine acyl-carnitine translocase (CACT) deficiency by comprehensive molecular analysis. Mol Genet Metab 2011 Aug;103(4):349-357

2. Rubio-Gozalbo ME, Bakker, JA, Waterham, HR, Wanders RJA: Carnitine-acylcarnitine translocase deficiency, clinical, biochemical and genetic aspects. Mol Aspects Med 2004 Oct-Dec;25(5-6):521-532

Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test