Familial encephalopathy with neuroserpin inclusion bodies (FENIB) is a progressive disorder of the

nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes ...

that is characterized by a loss of intellectual functioning (

dementia Dementia is a disorder which manifests as a set of related symptoms, which usually surfaces when the brain is damaged by injury or disease. The symptoms involve progressive impairments in memory, thinking, and behavior, which negatively affe ...

) and seizures. At first, affected individuals may have difficulty sustaining attention and concentrating. Their judgment, insight, and memory become impaired as the condition progresses. Over time, they lose the ability to perform the activities of daily living, and most people with this condition eventually require comprehensive care. The signs and symptoms of familial encephalopathy with

neuroserpin Neuroserpin is a protein that in humans is encoded by the ''SERPINI1'' gene. It is associated with Familial encephalopathy with neuroserpin inclusion bodies. Serine protease inhibitors of the serpin superfamily are involved in many cellular pro ...

inclusion bodies vary in their severity and age of onset. In severe cases, the condition causes seizures and episodes of sudden, involuntary muscle jerking or twitching (myoclonus) in addition to dementia. These signs can appear as early as a person's teens. Less severe cases are characterized by a progressive decline in intellectual functioning beginning in a person's forties or fifties. Mutations in the ''SERPINI1''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

cause familial encephalopathy with neuroserpin inclusion bodies. The ''SERPINI1'' gene provides instructions for making a protein called neuroserpin. This protein is found in

nerve cell A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. No ...

s, where it plays a role in the development and function of the nervous system. Neuroserpin helps control the

growth Growth may refer to: Biology * Auxology, the study of all aspects of human physical growth * Bacterial growth * Cell growth * Growth hormone, a peptide hormone that stimulates growth * Human development (biology) * Plant growth * Secondary growth ...

of nerve cells and their connections with one another, which suggests that this protein may be important for learning and memory. Mutations in the gene result in the production of an abnormally shaped, unstable version of neuroserpin. Abnormal neuroserpin proteins can attach to one another and form neuroserpin inclusion bodies or Collins bodies within nerve cells. Collins bodies form in cortical and subcortical neurons where they disrupt the cells' normal functioning and ultimately lead to cell death. Progressive dementia results from this gradual loss of nerve cells in certain parts of the brain. Researchers believe that a buildup of related, potentially toxic substances in nerve cells may also contribute to the signs and symptoms of this condition. This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In many cases, an affected person has a parent with the condition.

References

* National Library of Medicine
Genetics Home Reference - Familial encephalopathy with neuroserpin inclusion bodies

External links

{{Disorders of globin and globulin proteins Neurology Serpinopathies