BACKGROUND: Fatal familial insomnia (FFI) is an autosomal dominant disease linked to a mutation in the prion protein gene. Fatal familial insomnia is characterized by sleep disturbance and loss of neurons, with gliosis in the thalamic nuclei.OBJECTIVE: To describe the clinical, neurophysiological, radiological, and neuropathological data in a Chinese family with FFI.SETTING: Tertiary referral university hospital setting.PATIENTS: Patient 1 was a 36-year-old man who presented with insomnia and myoclonus.