Linkage exclusion in Italian families with hereditary essential tremor.

Essential tremor (ET) is a common movement disorder, with a prevalence of 0.4–3.93% in the general population. Up to 96% of patients with ET have a positive family history, suggesting that ET is primarily a hereditary disease. Although an autosomal dominant pattern of inheritance has been suggested, no human gene causative of ET has been identified yet. Genetic studies revealed linkage of familial ET to different chromosomal locations: 3q13.3, 2p25-p22 and 6p23 in families with European and Asian ancestry. Two independent studies excluded linkage to all previous loci in the Italian population, confirming additional underlying genetic heterogeneity. Herein, we tested for linkage to markers in 2p, 3q and 6p four large ET Italian families, comprising 29 affected individuals. The study did not provide any evidence of linkage to loci in 2p, 3q and 6p suggesting that the association with the disease is unlikely, in agreement with previous data on other Italian families.