Mitochondrial membrane protein-associated neurodegeneration

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Reviewed April 2014

What is mitochondrial membrane protein-associated neurodegeneration?

Mitochondrial membrane protein-associated neurodegeneration (MPAN) is a disorder of the nervous system. The condition typically begins in childhood or early adulthood and worsens (progresses) over time.

MPAN commonly begins with difficulty walking. As the condition progresses, affected individuals usually develop other movement problems, including muscle stiffness (spasticity) and involuntary muscle cramping (dystonia). Many people with MPAN have a pattern of movement abnormalities known as parkinsonism. These abnormalities include unusually slow movement (bradykinesia), muscle rigidity, involuntary trembling (tremors), and an inability to hold the body upright and balanced (postural instability).

Other neurological problems that occur in individuals with MPAN include degeneration of the nerve cells that carry visual information from the eyes to the brain (optic atrophy), which can impair vision; problems with speech (dysarthria); difficulty swallowing (dysphagia); and, in later stages of the condition, an inability to control the bowels or the flow of urine (incontinence). Additionally, affected individuals may experience a loss of intellectual function (dementia) and psychiatric symptoms such as behavioral problems, mood swings, hyperactivity, and depression.

MPAN is characterized by an abnormal buildup of iron in certain regions of the brain. Because of these deposits, MPAN is considered part of a group of conditions known as neurodegeneration with brain iron accumulation (NBIA).

How common is mitochondrial membrane protein-associated neurodegeneration?

MPAN is a rare condition that is estimated to affect less than 1 in 1 million people.

What genes are related to mitochondrial membrane protein-associated neurodegeneration?

Mutations in the C19orf12 gene cause MPAN. The protein produced from this gene is found in the membrane of cellular structures called mitochondria, which are the energy-producing centers of the cell. Although its function is unknown, researchers suggest that the C19orf12 protein plays a role in the maintenance of fat (lipid) molecules, a process known as lipid homeostasis.

The gene mutations that cause this condition lead to an altered C19orf12 protein that likely has little or no function. It is unclear how these genetic changes lead to the neurological problems associated with MPAN. Researchers are working to determine whether there is a link between problems with lipid homeostasis and brain iron accumulation and how these abnormalities might contribute to the features of this disorder.

How do people inherit mitochondrial membrane protein-associated neurodegeneration?

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Where can I find information about diagnosis or management of mitochondrial membrane protein-associated neurodegeneration?

These resources address the diagnosis or management of mitochondrial membrane protein-associated neurodegeneration and may include treatment providers.

You might also find information on the diagnosis or management of mitochondrial membrane protein-associated neurodegeneration 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 mitochondrial membrane protein-associated neurodegeneration?

You may find the following resources about mitochondrial membrane protein-associated neurodegeneration helpful. These materials are written for the general public.

MedlinePlus - Health information (3 links)
Additional NIH Resources - National Institutes of Health
National Institute of Neurological Disorders and Stroke: Dystonias Fact Sheet
Educational resources - Information pages (4 links)
Patient support - For patients and families
NBIA Disorders Association

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

Gene Reviews - Clinical summary (2 links)
Genetic Testing Registry - Repository of genetic test information (1 link)
PubMed - Recent literature
OMIM - Genetic disorder catalog

What other names do people use for mitochondrial membrane protein-associated neurodegeneration?

mitochondrial membrane protein-associated neurodegeneration due to C19orf12 mutation
mitochondrial protein-associated neurodegeneration
MPAN
NBIA4
neurodegeneration with brain iron accumulation 4

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 mitochondrial membrane protein-associated neurodegeneration?

Ask the Genetic and Rare Diseases Information Center

Where can I find general information about genetic conditions?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding mitochondrial membrane protein-associated neurodegeneration?

atrophy ; autosomal ; autosomal recessive ; bradykinesia ; cell ; dementia ; depression ;difficulty swallowing ; dysarthria ; dysphagia ; dystonia ; gene ; homeostasis ; hyperactivity ; incontinence ;involuntary ; involuntary trembling ; iron ; lipid ; mitochondria ; mutation ; nervous system ; neurological ;optic atrophy ; paraplegia ; parkinsonism ; protein ; recessive ; spasticity

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

References (6 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.