Two siblings with very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency suffered from rhabdomyolysis after l-carnitine supplementation

INTRODUCTION: Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is an autosomal recessive mitochondrial fatty acid oxidation disorder and presents as hypoketotic hypoglycemia or rhabdomyolysis during childhood. l-Carnitine supplementation for patients with VLCAD deficiency is controversial. Herein, we describe two siblings with VLCAD deficiency who experienced more frequent episodes of rhabdomyolysis after l-carnitine supplementation. CASE PRESENTATION: Case 1 involved a 6-year-old boy who was diagnosed with VLCAD deficiency after repeated episodes of hypoketotic hypoglycemia at 3 years of age. He developed rhabdomyolysis more frequently after starting l-carnitine supplementation. Case 2 involved an 8-year-old boy, the elder brother of case 1, who was also diagnosed with VLCAD deficiency by sibling screening at the age of 5 years. He first developed rhabdomyolysis during a common cold after treatment with l-carnitine. Both patients had fewer rhabdomyolysis episodes after the cessation of l-carnitine supplementation. CONCLUSION: Our cases suggest that l-carnitine supplementation can increase rhabdomyolysis attacks in patients with VLCAD deficiency.