Genetic heterogeneity in autosomal dominant essential tremor

Purpose: To perform linkage analysis of candidate loci in a large Midwester n family with autosomal dominant essential tremor. Methods: Thirty-eight me mbers of a six-generation family were evaluated for essential tremor using consensus criteria. Linkage analysis was performed with microsatellite mark ers reported for three genetic loci associated with familial essential trem or. Results: Patients exhibited a combination of postural and kinetic tremo r involving primarily the arms and hands, with a mean age of onset of 31 ye ars. Genetic studies excluded linkage to ETM1 and ETM2 loci, as well as a c andidate locus for parkinsonism and postural tremor on chromosome 4p. Concl usion: Familial essential tremor is a common hereditary movement disorder d emonstrating phenotypic variability and genetic heterogeneity.