Identification of FUS p.R377W in essential tremor

Background and purpose Exome sequencing analysis has recently identified a nonsense mutation in fused in sarcoma (FUS) segregating with essential tremor (ET) within a large French-Canadian family. Further characterization of FUS resulted in the identification of additional mutations in ET patients; however, their pathogenicity still remains to be confirmed. The role of FUS in an independent cohort of ET patients from Canada was evaluated. Methods The entire coding sequence of FUS in 217 patients diagnosed with ET was analyzed and two missense variants in 219 healthy controls were genotyped by Sanger sequencing. Results Sequencing of FUS identified a previously reported non-pathogenic mutation p.G174_G175del in one ET patient and two healthy controls, and a novel p.R377W in one patient with family history of disease. This mutation is highly conserved and strongly predicted to be damaging by in silico analysis. Conclusion This study has identified a novel FUS p.R377W substitution in ET patients. Additional genotyping studies in a large number of ET patients and controls are necessary to conclusively define its pathogenicity.