Carnitine-Acylcarnitine Translocase Deficiency. CACT deficiency.
Incidence
Carnitine-acylcarnitine translocase (CACT) deficiency is a disorder of long chain fatty acid oxidation. About 30 cases of this disorder have been reported. The disorder is inherited as an autosomal recessive trait.
Clinical Characteristics
CACT deficiency is a severe disease that can cause neonatal or infantile sudden death. Patients present in the newborn period with severe acute metabolic encephalopathy and arrhythmia. Pts had hypoketotic hypoglycemia, liver involvement, hepatomegaly, microvesicular esteatosis, generalized weakness, persistent hyperammonemia, cardiac hypertrophy, myopathy. In most patients the presenting features were neonatal neurological distress (lethargy, poor feeding), cardiac rhythm disorders and hypoketotic hypoglycemia with hyperammonemia. They may have frequent vomiting, apnea and respiratory insuficiency. Hepatomegaly and hypertrophic cardiomyopathy may develop secondarily. Plasma free carnitine is very reduced. Long chain acylcarnitine are elevated. Prenatal diagnosis is available by enzymatic or molecular analyses.
Precipitants
Fasting may induce coma and seizures
Provocation Tests
not recommended.
Diagnostic Procedures
Determination of the blood acylcarnitine profile and in vitro fatty acid oxidation studies in lymphocytes or fibroblasts are the two main ways to establish the diagnosis. Long chain acylcarnitine grossly elevated. Plasma free carnitine very reduced. EB-F. Urine organic acids are more or less informative for the biological diagnosis.