Fatal familial insomnia

What it is

A rare inherited human prion disease characterized by adult onset of progressive disturbance and loss of circadian rhythms, dysautonomia with increased sympathetic activity, and cognitive impairment with fluctuating vigilance, impaired long-term memory, disorientation, and oneiric states. Motor disturbances include myoclonus, cerebellar ataxia, and pyramidal signs. The disease rapidly leads to a somnolent or comatose state and is typically fatal after 9 or 30 months on average (bimodal course). Neuropathologic examination shows marked neuronal loss and gliosis predominantly in thalamic nuclei and inferior olives, while deposition of abnormal prion protein may be relatively sparse.

Key facts

Prevalence

<1 / 1 000 000

Age of onset

Adult

Inheritance

Autosomal dominant

Classified as

Disease

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Signs and symptoms

These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.

Gene

ICD-10 codes

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Related health topics

Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.

Cross-references