摘要
Dear Editor,Essential tremor(ET)is one of the most common movement disorders of unknown etiology[1,2],having an overall prevalence of 4%in the general population[2].The age at onset has been reported to be between 15 years and 20 years,and penetrance to be complete at between50 years and 70 years.It seems to be a progressive neurological disorder,and can lead to substantial disability in some patients.Although it presents some degree of clinical variability,it occurs in sporadic(SET)and familial(FET)forms with heterogeneity of expression between and within families[3].ET is characterized essentially by a postural and kinetic tremor most often affecting the arms,but it can also affect other parts of the body[4].Nonetheless,familial expression of ET has been linked to some loci[5–7].
