PSMB5 and essential tremor: SWEDD subjects encompass a heterogenous group of clinical phenotypes and some of these patients may have been misdiagnosed for essential tremor, dystonia, fragile X premutation, iatrogenic/tardive, vascular or brain neoplasms, psychogenic, supranigral parkinsonism, and soft extrapyramidal signs of the elderly, thus at least partially explaining why this cohort experienced a high degree of NMS burden [49–51].