Autosomal Recessive Axonal Neuropathy With Neuromyotonia: What's That?

Today's post from ghr.nlm.nih.gov (see link below) talks about Autosomal recessive axonal neuropathy with neuromyotonia, something you may never have heard of, even if you are an experienced neuropathy sufferer. It sounds complex and technical and something way outside our experience until you look at the symptoms as shown below and then it may sound much more familiar. If you have been diagnosed with this condition, you will have been through the mill of neuropathy testing to reach that point and most people will have received a much more general diagnosis long before that. Many people with neuropathy suffer some sort of increasing weakness and muscular atrophy (wasting) but most doctors will recognise that as a symptom of neuropathy and continue treatment as before. Actually this condition is due to a genetic mutation and is in most cases, hereditary but coming to that conclusion requires a very willing neurologist! If you are genuinely worried that your muscle wasting is abnormal, pester your doctor to investigate further.

Autosomal recessive axonal neuropathy with neuromyotonia
Reviewed: September 2014 Published: September 8, 2014

What is autosomal recessive axonal neuropathy with neuromyotonia?
 
Autosomal recessive axonal neuropathy with neuromyotonia is a disorder that affects the peripheral nerves. Peripheral nerves connect the brain and spinal cord to muscles and to sensory cells that detect sensations such as touch, pain, heat, and sound.

Axonal neuropathy, a characteristic feature of this condition, is caused by damage to a particular part of peripheral nerves called axons, which are the extensions of nerve cells (neurons) that transmit nerve impulses. In people with autosomal recessive axonal neuropathy with neuromyotonia, the damage primarily causes progressive weakness and wasting (atrophy) of muscles in the feet, legs, and hands. Muscle weakness may be especially apparent during exercise (exercise intolerance) and can lead to an unusual walking style (gait), frequent falls, and joint deformities (contractures) in the hands and feet. In some affected individuals, axonal neuropathy also causes decreased sensitivity to touch, heat, or cold, particularly in the lower arms or legs.

Another feature of this condition is neuromyotonia (also known as Isaac syndrome). Neuromyotonia results from overactivation (hyperexcitability) of peripheral nerves, which leads to delayed relaxation of muscles after voluntary tensing (contraction), muscle cramps, and involuntary rippling movement of the muscles (myokymia). 

How common is autosomal recessive axonal neuropathy with neuromyotonia?

Autosomal recessive axonal neuropathy with neuromyotonia is a rare form of inherited peripheral neuropathy. This group of conditions affects an estimated 1 in 2,500 people. The prevalence of autosomal recessive axonal neuropathy with neuromyotonia is unknown.

What genes are related to autosomal recessive axonal neuropathy with neuromyotonia?

Autosomal recessive axonal neuropathy with neuromyotonia is caused by mutations in the HINT1 gene. This gene provides instructions for making a protein that is involved in the function of the nervous system; however its specific role is not well understood. Laboratory studies show that the HINT1 protein has the ability to carry out a chemical reaction called hydrolysis that breaks down certain molecules; however, it is not known what effects the reaction has in the body.

HINT1 gene mutations that cause autosomal recessive axonal neuropathy with neuromyotonia lead to production of a HINT1 protein with little or no function. Sometimes the abnormal protein is broken down prematurely. Researchers are working to determine how loss of functional HINT1 protein affects the peripheral nerves and leads to the signs and symptoms of this condition.

Read more about the HINT1 gene.

How do people inherit autosomal recessive axonal neuropathy with neuromyotonia?

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 autosomal recessive axonal neuropathy with neuromyotonia?

You might find information on the diagnosis or management of autosomal recessive axonal neuropathy with neuromyotonia in Educational resources and Patient support.

General information about the diagnosis and management of genetic conditions is available in the Handbook.

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 autosomal recessive axonal neuropathy with neuromyotonia?

You may find the following resources about autosomal recessive axonal neuropathy with neuromyotonia helpful. These materials are written for the general public.
MedlinePlus - Health information
Genetic and Rare Diseases Information Center - Information about genetic conditions and rare diseases

Additional NIH Resources - National Institutes of Health (2 links)

Educational resources - Information pages (3 links)

Patient support - For patients and families (2 links)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.
OMIM - Genetic disorder catalog
What other names do people use for autosomal recessive axonal neuropathy with neuromyotonia?

ARAN-NM
autosomal recessive Charcot-Marie-Tooth disease type 2 with neuromyotonia
autosomal recessive neuromyotonia and axonal neuropathy
Gamstorp-Wohlfart syndrome
myokymia, myotonia, and muscle wasting
NMAN

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 autosomal recessive axonal neuropathy with neuromyotonia?

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.
What does it mean if a disorder seems to run in my family?
What are the different ways in which a genetic condition can be inherited?
If a genetic disorder runs in my family, what are the chances that my children will have the condition?
Why are some genetic conditions more common in particular ethnic groups?

These links provide additional genetics resources that may be useful.
Genetics and Health
Resources for Patients and Families
Resources for Health Professionals
 
What glossary definitions help with understanding autosomal recessive axonal neuropathy with neuromyotonia?

atrophy ; autosomal ; autosomal recessive ; axons ; cell ; contraction ; gait ; gene ; hydrolysis ; inherited ; involuntary ; joint ; motor ; myotonia ; nervous system ; neuropathy ; peripheral ; peripheral nerves ; peripheral neuropathy ; prevalence ; protein ; recessive ; sensitivity ; sensory cells ; syndrome ; wasting

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

See also Understanding Medical Terminology.

References (4 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.

http://ghr.nlm.nih.gov/condition/autosomal-recessive-axonal-neuropathy-with-neuromyotonia