A Novel Variant of the Short-Chain Enoyl-CoA Hydratase-1 Gene Presenting with a Mild Phenotype: The Second Case Report from India

Abstract A 9-year-old girl presented with asymmetric abnormal twisting movements affecting her left side more than the right side, initially action induced, but later persistent. Examination revealed generalized persistent dystonia with choreoathetosis and right partial tonic ocular tilt reaction. Brain magnetic resonance imaging showed T1 and T2 fluid-attenuated inversion recovery (FLAIR) hypointense and T2 hyperintense signal changes in bilateral globus pallidi. Clinical exome sequencing revealed compound heterozygous variatnts in enoyl-CoA hydratase-1 ( ECHS1 ) gene: a novel pathogenic variant in exon 6, chr10:g.133366045G > A (p.Gln224Ter) and a likely pathogenic variant in exon 5, chr10:g.133366990G > A (p.Ala173Val). Metabolic testing and arterial lactate levels were normal. She was treated with valine restricted diet, trihexiphenidyl, clonazepam, N-acetyl cysteine and mitochondrial cocktail, without significant improvement over the 6 months follow-up period.