Description of the condition

Adrenomyeloneuropathy (AMN) is a rare genetic disorder characterized by the accumulation of very long chain fatty acids (VLCFAs) due to mutations in the ABCD1 gene. AMN is a form of adrenoleukodystrophy that affects the spinal cord and body (peripheral nerves), resulting in symptoms like muscle weakness, difficulty walking, and bladder dysfunction. AMN in women is very varied, and it is not possible to predict how your AMN symptoms will progress. Treatment options vary based on the form and stage of the disease, and management focuses on addressing symptoms and supporting the patient’s well-being.

We have produced separate booklets for more practical information relevant to your condition.

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Cause

AMN is a genetically inherited disease caused by mutations (pathogenic variants) in the ABCD1 gene. It is X-linked meaning the gene is located on the X chromosome. Unlike women, men only have one X chromosome and they are generally more severely affected than females, although females are at risk of developing AMN.

Inheritance

X-linked recessive: The mutant gene is located on the X chromosome. Men have one X and one Y chromosome while women have two X chromosomes. This means that a female with a mutated gene on one X chromosome, will have the effects somewhat balanced by their second X chromosome without the mutation. However, a male with a mutated gene on their X chromosome will be affected as they only have one.

Often females find out that they have this gene due to a male member of the family being diagnosed. This can lead to feelings of guilt, especially if they have passed the gene on to their son. It is very common to have these feelings but it is important to remember that it is not your fault. Our counsellor and support services team can help you to work through these feelings. 

This image shows the inheritance of genes from parents to their children and the resulting combination of genes the child will have. Red represents the ALD gene, blue represents the normal copy of the gene, grey represents the Y gene that determines male sex. The line from each parent shows which gene they pass on to their child. The colours of the individuals tell the effect of the genes they have, red means they will have the ALD gene, blue means they will not have the ALD gene and are unaffected, and half red, half blue means they will have both the ALD gene and the normal gene.

Genetic counselling

Genetic counselling is essential for affected families due to the inheritance pattern of the condition. This is available at hospitals and Regional Genetic Centres. Please contact your doctor if you have any questions.

Learn more about genetic testing and counselling here.

Symptoms

Symptoms of Adrenomyeloneuropathy (AMN) can include stiffness, weakness and pain in the legs. This starts gradually and can progress over time. The medical term for this is ‘progressive spastic paraparesis’. Damage to the peripheral nerves supplying the legs means unsteadiness and falls are common. The nerves to the bladder and bowel can also be affected in AMN. Mobility can gradually deteriorate to the point where the sufferer eventually loses the ability to walk and becomes wheelchair bound. But this does not necessarily happen to all sufferers. Another common symptom is fatigue but this can vary from person to person.

Females are sometimes called ‘carriers’, because they can pass the gene to their children but were thought to be unaffected themselves. However, we now know that the ALD gene does cause effects in many women, therefore, we refer to females as ‘females with the ALD gene’. It is thought that about 80% of women with the ALD gene will develop some symptoms of AMN during their lifetime. Symptoms usually start around the ages of 40 to 50, but can begin earlier or later. Symptoms can vary in severity. In women, the development of either cerebral leukodystrophy or adrenal insufficiency is extremely rare –and has only been described in a very few isolated cases.

More symptom information

Learn more about specific symptoms of this leukodystrophy in these pages.

Treatments

Currently there is no treatment for AMN but there are promising clinical studies researching options. Treatment is unique to each person but generally focuses on alleviating symptoms of the disease such as muscle spasms, stiffness, and bowel and bladder problems.

If you have symptoms these should be discussed with your doctor.

Though adrenal insufficiency is extremely rare for women, steroid replacement therapy is available for treating adrenal insufficiency and generally improves the patient’s quality of life.

There is condition management information that may be useful for you in managing your or your loved one’s leukodystrophy.

Current research

There may be a current clinical trial, natural history study or patient registry for your condition. Check our current research page and ask your specialist doctor for more information.

Why Adding Your Variant to the ABCD1 Variant Registry Matters

Dr. Stephan Kemp is a Professor at the Amsterdam University Medical Centers (AMC), University of Amsterdam, the Netherlands. With over 20 years of experience in adrenoleukodystrophy (ALD) research and more than 80 scientific publications, Dr. Kemp is a leading expert in the field. In 1999, together with Dr. Hugo Moser, he helped create the ALD database now known as the ABCD1 Variant Registry.

The ABCD1 Variant Registry collects and records changes (variants or mutations) in the ABCD1 gene which is the gene responsible for adrenoleukodystrophy and adrenomyeloneuropathy (AMN). A genetic variant simply means a change in the DNA. Some variants are harmless (benign), while others known as pathogenic variants can cause disease. In ALD, a pathogenic variant in the ABCD1 gene alters how the body processes very long-chain fatty acids, leading to ALD and AMN. For more information, visit The ABCD1 Variant Registry.

Each variant added to the ABCD1 registry helps researchers and clinicians better understand:

  • Whether a specific change in the gene causes disease (pathogenic)
  • Clinical effects it may have, such as adrenal disease, myeloneuropathy, or cerebral ALD

The strength of this registry lies in collaboration. Diagnostic laboratories, researchers, physicians, and families all contribute information to improve understanding of how different ABCD1 variants affect people.

By sharing your or your family’s ABCD1 variant, you help strengthen this global resource by:

  • Enabling faster diagnosis
  • Improving genetic counselling
  • Supporting better treatment and care for everyone affected by ALD.

If you would like to add your ABCD1 variant to the registry, please contact: Professor Stephan Kemp at s.kemp@amsterdamumc.nl

Scientific research

We understand that research is a significant priority and source of hope for the leukodystrophy community. There is more research in leukodystrophy now than ever before. Alex TLC actively promotes and supports research in a number of ways.

Every month we update our database of research summaries with the most recent research. This includes summaries of leukodystrophy articles, clinical trials and pharmaceutical press releases. Our summaries allow our community to read about relevant recent research developments in a format that is easily understood.

How we can support you

Learn about the ways in which we can help in the how we support you section. When you or a family member been diagnosed with a leukodystrophy it may be difficult to know where to go for more advice – this information could help.

How we support you

Services and equipment

Our services and equipment section is here to help leukodystrophy patients and their families manage their condition. All information is based on our knowledge of UK services, however, our team are happy to receive support requests from other countries – email us.

Services and equipment

Healthcare professionals

You may be introduced to many different medical professionals which you may find confusing. View our guide to the health and care professionals you may encounter, with short descriptions about what they do.

Health and care professionals

Links to useful information

We take great care in only selecting credible, useful links and resources, however we cannot be held responsible for the content of external websites or other sources.

View the full list of leukodystrophies