Clinical, Biochemical and Molecular Characterization of Short-Chain Enoyl-CoA Hydratase (ECHS1) Deficiency.

Short-chain enoyl-CoA hydratase (ECHS1) (OMIM 602292) deficiency is a rare autosomal recessive inborn error of metabolism caused by pathogenic variants in the ECHS1 gene. Features of encephalopathy, movement disorders, developmental delay, high lactate, seizures, and basal ganglia abnormalities were reported with this disorder. Exome sequencing is a powerful tool for the identification of Leigh-like disorders, especially in the absence of biochemical biomarkers. We describe an 11-month-old infant who presented with metabolic acidosis and developed movement disorder and was found to have elevated C4OH and basal ganglia lesion in the brain. Urine organic acids showed the presence of branch chain amino acid metabolites. Whole-exome sequencing identified a previously reported homozygous pathogenic variant in the ECHS1 gene (c.C518T (p.Ala173Val).