Genetic heterogeneity in autosomal dominant essential tremor

Purpose: To perform linkage analysis of candidate loci in a large Midwestern family with autosomal dominant essential tremor. Methods: Thirty-eight members of a six-generation family were evaluated for essential tremor using consensus criteria. Linkage analysis was performed with microsatellite markers reported for three genetic loci associated with familial essential tremor. Results: Patients exhibited a combination of postural and kinetic tremor involving primarily the arms and hands, with a mean age of onset of 31 years. Genetic studies excluded linkage to ETM1 and ETM2 loci, as well as a candidate locus for parkinsonism and postural tremor on chromosome 4p. Conclusion: Familial essential tremor is a common hereditary movement disorder demonstrating phenotypic variability and genetic heterogeneity.