Acylcarnitine analysis is a useful investigation in other cases of suspected mitochondrial disease, since it may help to direct diagnostic genetic investigations, for example succinyl and propionyl carnitines may be elevated in patients with succinyl-CoA ligase deficiency caused by SUCLA2 or SUCLG1 mutations [38,39]. This evidence concerns the gene SUCLG1 and inborn mitochondrial metabolism disorder.