Summary

Acyl-CoA dehydrogenase very long chain (VLCAD) deficiency is an inborn error of mitochondrial long-chain fatty acid oxidation, inherited as an autosomal recessive trait. VLCAD is an electron transfer flavoprotein (ETF)-dependant enzyme, located in mitochondrial internal matrix.The severe form of the disease is characterised by recurrent episodes of hypoketotic hypoglycemia, often associated with hypertrophic cardiomyopathy with pericardial effusion, or arrythmia, which can lead to a cardiorespiratory arrest. These symptoms can occur during the neonatal period and, in all cases, before the second year of age. The treatment includes glucose infusion and high caloric supply with medium chain triglycerides in order to stop lypolysis, and L-carnitine supplementation (50 to 100 mg/kg/day). During late childhood and adulhood, the disease can present as exercise intolerance, muscle pain, recurrent episodes of rhabdomyolysis, triggered by fast, cold, fever or prolonged exercise. Urinary organic acid profile is poorly informative Conversely, plasma long-chain fatty acid (C14:1) and acylcarnitine profiles allow to suspect the diagnosis. The disease is confirmed by the measurement of VLCAD activity in cultured skin fibroblasts, lymphocytes or tissue biopsies. Prenatal diagnosis is available by enzyme measurement in trophoblastic cells (biopsy or cultured cells) or amniotic fluid cells. Molecular study reveals a high number of mutations

Expert reviewer(s)

• Dr Christine VIANEY-SABAN