Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is a rare genetic metabolic disorder involving impaired fatty acid β-oxidation. It is caused by mutations in the Acyl-CoA Dehydrogenase Very Long Chain (ACADVL) gene, which encodes the VLCAD enzyme. The clinical presentation is diverse, ranging from a severe neonatal-onset form to a milder adult-onset form. We describe the first reported case in Vietnam, which is a 20-year-old man who presented with exercise intolerance, myalgia, and recurrent rhabdomyolysis triggered by fasting and exertion. Acylcarnitine profiling suggested a fatty acid oxidation disorder, and whole-exome sequencing identified the diagnosis of VLCAD deficiency with c747G > T (p.Trp249Cys) mutation. It has not previously been reported in the Vietnamese population. This case highlights the important role of neonatal screening and genetic testing in the early diagnosis of metabolic myopathies. In addition, it raises awareness of genetic disorders among healthcare providers and the public in developing countries.
