NovelSERAC1Variant Presenting With Adult-Onset Extrapyramidal Dystonia-Parkinsonism Phenotype

ObjectivesTo report a novel likely pathogenic variant in theSERAC1gene associated with early adult-onset parkinsonism and progressive dystonia.MethodsClinical, biochemical, and imaging assessments were performed on 2 affected adult brothers with a genetically unsolved progressive neurologic disorder followed by whole-genome sequencing.ResultsA homozygous likely pathogenic variant in theSERAC1gene (c.[129-2A > C], p.[(?)];[(?)]) was discovered.DiscussionWe describe a novel homozygous variant in the serine active site-containing protein 1 gene (SERAC1) in 2 brothers with a progressive extrapyramidal movement disorder of early onset parkinsonism and dystonia. Previous variants have been associated with a severe 3-methylglutaconic aciduria with dystonia, deafness, hepatopathy, encephalopathy and Leigh-like syndrome, or juvenile onset complicated spastic paraparesis. Our cases expand the phenotype ofSERAC1variants, with an adult-onset presentation of dystonia-parkinsonism.