ACADVL and very long chain acyl-CoA dehydrogenase deficiency: Pathogenic variants in ACADVL result in very long-chain acyl-CoA dehydrogenase deficiency (VLCADD), an autosomal recessive disorder with a worldwide incidence of 1:30,000 to 1:100,000, leading to the accumulation of high blood levels of long-chain acylcarnitine conjugates, especially the tetradecenoyl (C14:1) acylcarnitine [2,4].