Disease Information for Fatal Familial Insomnia

Fatal Familial Insomnia (FFI) is a rare, rapidly progressive, degenerative brain disorder that is transmitted as an autosomal dominant trait; The disorder typically becomes apparent during middle age or later life and is characterized by an inability to sleep or abnormal wakefulness that is resistant to treatment (intractable insomnia) and impaired functioning of the portion of the nervous system (ie, autonomic nervous system) that regulates certain involuntary functions (dysautonomia); Dysautonomia may be characterized by fever (pyrexia), profuse sweating (diaphoresis), abnormal contraction of the pupils (miosis), and other associated findings; Individuals with FFI may also develop slurred, slowed speech (dysarthria); memory impairment and attention disturbances; complex hallucinations that may be described as "dream-like" states; and neuromuscular abnormalities; These may include increased reflex responses (hyperreflexia); impaired coordination of voluntary movements (ataxia); tremors; and involuntary, shock-like contractions of certain muscles (myoclonus); Neurodegenerative changes associated with FFI may be limited to certain regions of the brain (eg, thalamic nuclei); Fatal familial insomnia is caused by a specific mutation of the PRNP gene on chromosome 20---------------[NORD 2005]---------------------

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