Effort to differentiate essential tremor plus and dystonic tremor using whole exome sequencing: an exploratory study.

Background: The clinical differentiation between essential tremor plus (ETP) and dystonic tremor (DT) is challenging. This study aimed at the genetic diagnosis of ETP and DT. Methods: Whole exome sequencing was performed on 50 probands (ETP = 25; DT = 25) and analysed to identify variants in known genes linked with dystonia and essential tremor plus phenotypes. Results: We identified pathogenic/likely pathogenic variants [THAP1 (n = 1) and ANO3 (n = 1)] in two patients with DT. In addition, one DT patient had a variant of uncertain significance in FUS and four patients had benign variants [CIZ1 (n = 1), COL6A3 (n = 1), GCH1 (n = 1), TENM4 (n = 1)]. One patient with ETP was detected to have a variant of uncertain significance in TENM4 and five patients with ETP had benign variants [COL6A3 (n = 2), VPS16 (n = 1), TAF1 (n = 1), KMT2B (n = 1)]. Conclusion: Genetic studies may be in an important biomarker in differentiating patients with ET plus from DT which is challenging in a clinical setting. [ABSTRACT FROM AUTHOR]