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Familial encephalopathy with neuroserpin inclusion bodies

(often shortened to FENIB)
Reviewed April 2009

What is FENIB?

Familial encephalopathy with neuroserpin inclusion bodies (FENIB) is a disorder that causes progressive dysfunction of the brain (encephalopathy). It is characterized by a loss of intellectual functioning (dementia) and seizures. At first, affected individuals may have difficulty sustaining attention and concentrating. They may experience repetitive thoughts, speech, or movements. As the condition progresses, their personality changes and judgment, insight, and memory become impaired. Affected people lose the ability to perform the activities of daily living, and most eventually require comprehensive care.

The signs and symptoms of FENIB 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.

How common is FENIB?

This condition appears to be rare; only a few affected individuals have been reported worldwide.

What genes are related to FENIB?

FENIB results from mutations in the SERPINI1 gene. This gene provides instructions for making a protein called neuroserpin, which is found in nerve cells (neurons). Neuroserpin plays a role in the development and function of the nervous system. This protein helps control the growth of neurons and their connections with one another, which suggests that it may be important for learning and memory.

Mutations in the SERPINI1 gene result in the production of an abnormally shaped, unstable form of neuroserpin. Within neurons, defective neuroserpin proteins can attach to one another and form clumps called neuroserpin inclusion bodies or Collins bodies. These clumps disrupt the cells' normal functioning and ultimately lead to cell death. The gradual loss of neurons in certain parts of the brain causes progressive dementia. Researchers believe that a buildup of related, potentially toxic substances in neurons may also contribute to the signs and symptoms of this condition.

Read more about the SERPINI1 gene.

How do people inherit FENIB?

FENIB 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.

Where can I find information about diagnosis or management of FENIB?

These resources address the diagnosis or management of FENIB and may include treatment providers.

You might also find information on the diagnosis or management of FENIB in Educational resources and Patient support.

General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.

To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.

Where can I find additional information about FENIB?

You may find the following resources about FENIB helpful. These materials are written for the general public.

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

What other names do people use for FENIB?

  • familial dementia with neuroserpin inclusion bodies

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines and How are genetic conditions and genes named? in the Handbook.

What if I still have specific questions about FENIB?

Where can I find general information about genetic conditions?

What glossary definitions help with understanding FENIB?

autosomal ; autosomal dominant ; cell ; dementia ; encephalopathy ; epilepsy ; ER ; familial ; gene ; inclusion bodies ; inherited ; involuntary ; myoclonus ; nervous system ; protein ; toxic

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

See also Understanding Medical Terminology.

References (9 links)


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.

Reviewed: April 2009
Published: February 8, 2016