Objective Fatal familial insomnia (FFl) is an autosomal dominant prion disease characterized clinically by inattention,sleep loss,dysautonomia,and motor signs.This study is aimed to investigate clinical and familial characteristics of ten Chinese Patients with FFI.Methods We identified ten FFl cases from the surveillance network for Creutafeldt- Jakob disease (CJD) in China.Final diagnosis of FFl cases was made in accordance with the WHO criteria for CJD.The main clinical features and family histories of these ten FFI cases were analyzed.Results The median age of ten cases at onset was 38 years (from 19 to 55).The foremost symptoms seemed to be various,including sleep disturbances,vision disorder,dizziness and anorexia.Sleep disturbances appeared in all cases and lasted in the whole clinical courses.Progressive sympathetic symptoms,memory loss,movement disturbances,myoclonus and hypertension were also frequently observed.The median duration of the disease was 9.5 months.EEG and MRI did not figure out special abnormality.14-3-3 protein in CSF was positive in five out of eight tested patients.Clear family histories were identified in 8 patients.Conclusion The data from our study confirm that the Chinese FFl cases have similar clinical characteristics as that of the Caucasian cases.Compared with other genetic CJD associated mutations,the genetic frequencies of D178N in PRNP are apparently high among the Chinese cases.