Familial encephalopathy with neuroserpin inclusion bodies

Familial encephalopathy with neuroserpin inclusion bodies (FENIB) is a disorder that causes progressive dysfunction of the brain (encephalopathy). This condition is characterized by a loss of intellectual functioning (dementia) and seizures.

The first signs of intellectual impairment in individuals with FENIB may be problems with attention and concentration. Affected individuals may have trouble regulating their thoughts or speech. As the condition progresses, personality changes develop, and judgment, insight, and memory become impaired. Affected individuals lose the ability to perform the activities of daily living, and most eventually require comprehensive care.

People with FENIB have seizures that involve a sudden, involuntary muscle jerking or twitching (myoclonus). Many also experience at least one other form of seizure, typically generalized seizures that involve a loss of consciousness, muscle rigidity, and convulsions. In rare cases, people with FENIB have prolonged episodes of seizure activity that last several minutes (status epilepticus). In most people with FENIB, anti-seizure medications are not effective. Many people with FENIB have other types of involuntary movement (dyskinesia).

The signs and symptoms of FENIB can appear at any age, and they vary in severity. In severe cases, dementia can appear in childhood or adolescence and is often the first sign of the condition. Less severe cases are characterized by a progressive decline in intellectual functioning that begins in mid- to late adulthood.

People with FENIB have a shortened life expectancy. The earlier the signs and symptoms appear, the greater the impact on life expectancy. Causes of death in people with FENIB include status epilepticus and pneumonia.