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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®

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.

Related Gene(s)

Changes in this gene are associated with familial encephalopathy with neuroserpin inclusion bodies.


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.

  • Genetic Testing Registry: Familial encephalopathy with neuroserpin inclusion bodies (
  • MedlinePlus Encyclopedia: Dementia (
  • MedlinePlus Encyclopedia: Seizures (

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?

Ask the Genetic and Rare Diseases Information Center (

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.


  • Bradshaw CB, Davis RL, Shrimpton AE, Holohan PD, Rea CB, Fieglin D, Kent P, Collins GH. Cognitive deficits associated with a recently reported familial neurodegenerative disease: familial encephalopathy with neuroserpin inclusion bodies. Arch Neurol. 2001 Sep;58(9):1429-34. (
  • Coutelier M, Andries S, Ghariani S, Dan B, Duyckaerts C, van Rijckevorsel K, Raftopoulos C, Deconinck N, Sonderegger P, Scaravilli F, Vikkula M, Godfraind C. Neuroserpin mutation causes electrical status epilepticus of slow-wave sleep. Neurology. 2008 Jul 1;71(1):64-6. doi: 10.1212/01.wnl.0000316306.08751.28. (
  • Davis RL, Holohan PD, Shrimpton AE, Tatum AH, Daucher J, Collins GH, Todd R, Bradshaw C, Kent P, Feiglin D, Rosenbaum A, Yerby MS, Shaw CM, Lacbawan F, Lawrence DA. Familial encephalopathy with neuroserpin inclusion bodies. Am J Pathol. 1999 Dec;155(6):1901-13. (
  • Davis RL, Shrimpton AE, Carrell RW, Lomas DA, Gerhard L, Baumann B, Lawrence DA, Yepes M, Kim TS, Ghetti B, Piccardo P, Takao M, Lacbawan F, Muenke M, Sifers RN, Bradshaw CB, Kent PF, Collins GH, Larocca D, Holohan PD. Association between conformational mutations in neuroserpin and onset and severity of dementia. Lancet. 2002 Jun 29;359(9325):2242-7. Erratum in: Lancet 2002 Oct 5;360(9339):1102. (
  • Davis RL, Shrimpton AE, Holohan PD, Bradshaw C, Feiglin D, Collins GH, Sonderegger P, Kinter J, Becker LM, Lacbawan F, Krasnewich D, Muenke M, Lawrence DA, Yerby MS, Shaw CM, Gooptu B, Elliott PR, Finch JT, Carrell RW, Lomas DA. Familial dementia caused by polymerization of mutant neuroserpin. Nature. 1999 Sep 23;401(6751):376-9. (
  • Galliciotti G, Sonderegger P. Neuroserpin. Front Biosci. 2006 Jan 1;11:33-45. Review. (
  • Gourfinkel-An I, Duyckaerts C, Camuzat A, Meyrignac C, Sonderegger P, Baulac M, Brice A. Clinical and neuropathologic study of a French family with a mutation in the neuroserpin gene. Neurology. 2007 Jul 3;69(1):79-83. (
  • Miranda E, MacLeod I, Davies MJ, Pérez J, Römisch K, Crowther DC, Lomas DA. The intracellular accumulation of polymeric neuroserpin explains the severity of the dementia FENIB. Hum Mol Genet. 2008 Jun 1;17(11):1527-39. doi: 10.1093/hmg/ddn041. Epub 2008 Feb 11. (
  • Yepes M, Lawrence DA. Neuroserpin: a selective inhibitor of tissue-type plasminogen activator in the central nervous system. Thromb Haemost. 2004 Mar;91(3):457-64. Review. (


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 1, 2016