Rare Pediatrics News

Disease Profile

Adrenomyeloneuropathy

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

0

US Estimated

Europe Estimated

Age of onset

Adult

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ICD-10

E71.3

Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

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Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Other names (AKA)

AMN

Categories

Congenital and Genetic Diseases; Endocrine Diseases; Male Reproductive Diseases;

Summary

Adrenomyeloneuropathy (AMN) is an inherited condition that affects the spinal cord. It is a form of X-linked adrenoleukodystrophy. On average, people with AMN begin to develop features in the late twenties. Signs and symptoms may include progressive stiffness and weakness of the legs; ataxia; speech difficulties; adrenal insufficiency; sexual dysfunction; and bladder control issues. Some people with AMN also have brain involvement which can lead to behavioral abnormalities, vision loss, hearing problems, and/or seizures.[1][2] AMN is caused by changes (mutations) in the ABCD1 gene and is inherited in an X-linked manner.[3][4] Treatment addresses the symptoms in each person and may include steroid replacement therapy for adrenal insufficiency.[2][4]

Symptoms

Adrenomyeloneuropathy (AMN) is a form of X-linked adrenoleukodystrophy. On average, people with AMN begin to develop symptoms at age 28; however, the age of onset can range from the second to the fifth decade of life. There are two forms of AMN that vary in severity. The milder form of the condition (AMN without cerebral involvement) only affects the spinal cord, while the more severe form (AMN with cerebral involvement) affects both the brain and the spinal cord.[1]

Signs and symptoms of AMN vary, but may include:[1][2][3]

  • Difficulty walking
  • Changes in gait (style of walking)
  • Progressive stiffness and weakness of the legs
  • Ataxia
  • Hypertonia
  • Speech difficulties
  • Adrenal insufficiency
  • Sexual dysfunction and/or impotence
  • Problems with bladder control
  • Mild peripheral neuropathy
  • Weight loss
  • Nausea

In addition to the symptoms above, people with AMN with cerebral involvement may develop behavioral abnormalities, vision loss, hearing problems and/or seizures.[2]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
HPO ID
Percent of people who have these symptoms is not available through HPO
Abnormality of the cerebral white matter
0002500
Alopecia
Hair loss
0001596
Attention deficit hyperactivity disorder
Attention deficit
Attention deficit disorder
Attention deficit-hyperactivity disorder
Attention deficits
Childhood attention deficit/hyperactivity disorder

[ more ]

 0007018
Blindness
0000618
Bowel incontinence
Loss of bowel control
0002607
Bulbar palsy
0001283
Dementia
Dementia, progressive
Progressive dementia

[ more ]

 0000726
Elevated circulating long chain fatty acid concentration
0003455
Hearing impairment
Deafness
Hearing defect

[ more ]

 0000365
Hyperpigmentation of the skin
Patchy darkened skin
0000953
Hypogonadism
Decreased activity of gonads
0000135
Impaired vibration sensation at ankles
Decreased vibration sense at ankles
Decreased vibration sense in feet

[ more ]

 0006938
Impotence
Difficulty getting a full erection
Difficulty getting an erection

[ more ]

 0000802
Incoordination
Difficulties in coordination
Incoordination of limb movements
Limb incoordination

[ more ]

 0002311
Limb ataxia
0002070
Loss of speech
0002371
Lower limb muscle weakness
Lower extremity weakness
Lower limb weakness
Muscle weakness in lower limbs

[ more ]

 0007340
Neurodegeneration
Ongoing loss of nerve cells
0002180
Paraparesis
Partial paralysis of legs
0002385
Polyneuropathy
Peripheral nerve disease
0001271
Primary adrenal insufficiency
0008207
Progressive
Worsens with time
0003676
Psychosis
0000709
Seizure
0001250
Slurred speech
0001350
Spastic paraplegia
0001258
Truncal ataxia
Instability or lack of coordination of central trunk muscles
0002078
Urinary bladder sphincter dysfunction
0002839
Urinary incontinence
Loss of bladder control
0000020
Visual loss
Loss of vision
Vision loss

[ more ]

 0000572
X-linked recessive inheritance
0001419
Do you have updated information on this disease? We want to hear from you.

Cause

Adrenomyeloneuropathy (AMN) is caused by changes (mutations) in the ABCD1 gene. This gene gives the body instructions to make the adrenoleukodystrophy protein (ALDP) which helps transport certain types of fats (called very long-chain fatty acids) into the peroxisomes. Peroxisomes are structures in cells that contain enzymes used to help break down fats and other substances. Mutations in the ABCD1 gene cause low levels of functional ALDP, which then causes high levels of very long-chain fatty acids to build up in the body. High levels of these fats in the nervous system, adrenal glands, and testes disrupt their normal function, resulting in the features of AMN.[3]

Diagnosis

A diagnosis of adrenomyeloneuropathy (AMN) is typically suspected based on the presence of characteristic signs and symptoms. A blood test that measures the levels of a specific type of fat (very long-chain fatty acids) and/or genetic testing for a mutation in the ABCD1 gene can be used to confirm the diagnosis. Once a diagnosis is made, an MRI of the brain may be recommended to determine if the person has AMN with cerebral involvement (brain and spinal cord affected) or AMN without cerebral involvement (only spinal cord affected).[4][1][2]

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

    Treatment

    Treatment of adrenomyeloneuropathy (AMN) varies based on the signs and symptoms in each person. For example, steroid replacement therapy may be prescribed in people with adrenal insufficiency. Physical therapy may also be recommended to help build and maintain muscle strength.[1][2][4]

    Organizations

    Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

    Organizations Supporting this Disease

      Organizations Providing General Support

        Learn more

        These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

        Where to Start

        • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
        • Genetics Home Reference (GHR) contains information on Adrenomyeloneuropathy. This website is maintained by the National Library of Medicine.
        • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.
        • The United Leukodystrophy Foundation has developed an information page on Adrenomyeloneuropathy. Click on the link above to view this information page.

          In-Depth Information

          • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
          • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
          • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
          • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
          • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
          • PubMed is a searchable database of medical literature and lists journal articles that discuss Adrenomyeloneuropathy. Click on the link to view a sample search on this topic.

            References

            1. Adrenomyeloneuropathy (AMN). United Leukodystrophy Foundation. https://ulf.org/adrenomyeloneuropathy-amn.
            2. Alan K Percy, MD; Ronald JA Wanders, PhD. Adrenoleukodystrophy. UpToDate. February 2015;
            3. X-linked adrenoleukodystrophy. Genetics Home Reference. July 2013; https://ghr.nlm.nih.gov/condition/x-linked-adrenoleukodystrophy.
            4. Steven J Steinberg, PhD, Ann B Moser, BA, and Gerald V Raymond, MD. X-Linked Adrenoleukodystrophy. GeneReviews. April 2012; https://www.ncbi.nlm.nih.gov/books/NBK1315/.

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