National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is a genetic disease that affects the nervous system and the adrenal glands (small glands located on top of each kidney). People with this disease often have progressive loss of the fatty covering (myelin) that surrounds the nerves in the brain and spinal cord. They may also have a shortage of certain hormones that is caused by damage to the outer layer of the adrenal glands (adrenal cortex). This is called adrenocortical insufficiency, or Addison disease.[1] There are three forms of X-ALD: a childhood cerebral form, an adrenomyeloneuropathy (AMN) type, and an adrenal-insufficiency-only-type. The disease primarily affects males.[1]

X-ALD is caused by a variation (mutation) in the ABCD1 gene and it is inherited in an X-linked. manner. Diagnosis of the disease is based on testing the levels of a molecule called very long-chain fatty acids (VLCFA). The diagnosis can be confirmed with genetic testing. There is still no cure for X-ALD, but taking special oils such as Lorenzo’s oil can lower the blood levels of VLCFA. Bone marrow transplantation may be an option for boys who have evidence of brain involvement on MRI, but do not yet have obvious symptoms of the disease with a normal neurological exam. Adrenocortical insufficiency is treated with corticosteroids.[2] 
Last updated: 2/12/2018
X-linked adrenoleukodystrophy (X-ALD) symptoms are very varied. Basically there are three main types that are present in about 90% or 95% of the affected people: a childhood cerebral form or symptoms set 1, an adrenomyeloneuropathy (AMN) type or symptoms set 2, and an adrenal insufficiency-only type, or symptoms set 3.  There are other other less common  presentations (types) of the disease, known as symptoms sets 4 to 8:
  • Childhood cerebral form of X-ALD (or symptoms set 1):  It mostly present with neurological problems, and typically begin between ages 4-8 years-old. The first noticeable symptom is usually behavior problems in school such as struggling to pay attention. Some boys may have seizures as their first symptom. As the disease progresses, other symptoms may include vomiting, vision loss, learning disabilities, trouble eating (dysphagia), deafness, fatigue, and trouble coordinating movements (ataxia).[2][3]
  • Adrenomyeloneuropathy (AMN) type (or symptoms set 2):  Presents with both adrenal and neurological problems. It usually begin in early to mid-adulthood, and it is the most common presentation.  Symptoms can include leg stiffness, weakness and pain in the hands and feet (peripheral neuropathy), muscle spasms and weakness, and urinary problems or sexual dysfunction.[2]
  • Adrenal insufficiency-only (Addison disease-only) type (or symptoms set 3): It is characterized by adrenal insufficiency without neurologic problems. Symptoms of adrenal insufficiency can develop at any time between childhood and adulthood and include decreased appetite, increased pigment (melanin) in the skin making it appear darker, muscle weakness, and vomiting.[4]
Symptoms seen in about 5%-10% of affected males may include:[2]
  • Symptom set 4: Onset is between age four and ten years but may occur in adolescence or, rarely, in adults, and may include headache, increased intracranial pressure, paralysis of one side of the body (hemiparesis) or visual field defect, difficulty speaking or other signs of localized brain disease.
  • Symptom set 5: Progressive behavioral disturbance, dementia, and paralysis in an adult
  • Symptom set 6: Progressive lack of coordination in a child or adult
  • Symptom set 7: Problems with urination and bowel abnormalities and occasionally impotence in at-risk males who have other affected relatives
  • Symptom set 8. No evidence of neurologic or endocrine dysfunction
Approximately 20% of female who are carriers develop mild to moderate weakness and spasticity (stiffness) of the legs (spastic paraparesis) in middle age or later. Adrenal function is usually normal.[2]

Last updated: 2/12/2018

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.

Showing of 54 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Abnormality of metabolism/homeostasis
Laboratory abnormality
Metabolism abnormality
[ more ] 		0001939
Attention deficit hyperactivity disorder
Attention deficit
Attention deficit disorder
Attention deficit-hyperactivity disorder
Attention deficits
Childhood attention deficit/hyperactivity disorder
[ more ] 		0007018
Clumsiness 0002312
Dementia
Dementia, progressive
Progressive dementia
[ more ] 		0000726
Functional motor deficit 0004302
Gait disturbance
Abnormal gait
Abnormal walk
Impaired gait
[ more ] 		0001288
Headache
Headaches
0002315
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ] 		0001249
Leg muscle stiffness 0008969
Progressive hearing impairment 0001730
Progressive spastic paraparesis 0007199
Sensory impairment 0003474
Specific learning disability 0001328
Visual loss
Loss of vision
Vision loss
[ more ] 		0000572
30%-79% of people have these symptoms
Adrenal insufficiency 0000846
Aggressive behavior
Aggression
Aggressive behaviour
Aggressiveness
[ more ] 		0000718
Aphasia
Difficulty finding words
Losing words
Loss of words
[ more ] 		0002381
Disinhibition 0000734
Hemiparesis
Weakness of one side of body
0001269
Inappropriate sexual behavior 0008768
Increased circulating ACTH level
High blood corticotropin levels
0003154
Increased intracranial pressure
Rise in pressure inside skull
0002516
Neurogenic bladder
Lack of bladder control due to nervous system injury
0000011
Urinary bladder sphincter dysfunction 0002839
Visual field defect
Partial loss of field of vision
0001123
5%-29% of people have these symptoms
Diplopia
Double vision
0000651
Impotence
Difficulty getting a full erection
Difficulty getting an erection
[ more ] 		0000802
Paralysis
Inability to move
0003470
Percent of people who have these symptoms is not available through HPO
Abnormality of the cerebral white matter 0002500
Alopecia
Hair loss
0001596
Blindness 0000618
Bowel incontinence
Loss of bowel control
0002607
Bulbar palsy 0001283
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
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 incontinence
Loss of bladder control
0000020
X-linked recessive inheritance 0001419
Showing of 54 |
Last updated: 7/1/2020
X-linked adrenoleukodystrophy (X-ALD) is caused by a variation (mutation) in the ABCD1 gene. This  gene provides instructions to make a protein called the adrenoleukodystrophy protein (ALDP). ALDP normally moves  a type of fat molecule called very long-chain fatty acids (VLCFA) into a special part of the cell to be broken down. When the ABCD1 gene is changed, there is too little ALDP in the cells or the ALDP that is made does not work normally. This causes VLCFA to build up in the body. High levels of VLCFA are thought to be damaging to the outside of the adrenal glands (adrenal cortex) and the fatty covering (myelin) that surrounds the nerve cells in the brain and spinal cord. Researchers believe the damage caused by VLCFA may involve inflammation, especially in the brain.[1][2]
Last updated: 2/12/2018
X-linked adrenoleukodystrophy (X-ALD) is inherited in an X-linked manner.[1] This means that the ABCD1 gene is located on the X chromosome. The X chromosome is one of the sex chromosomes. Each woman has two X chromosomes, and each man has one X chromosome and one Y chromosome. Because men have only one X chromosome, they only have one copy of the ABCD1 gene. If this gene has a disease-causing change, they will have X-ALD.

Women who have disease-causing changes in one copy of the ABCD1 gene are known as carriers of the disease. About 80% of carriers do not have signs or symptoms of X-ALD because they have another working copy of ABCD1. However, about 20% of female carriers have symptoms that are similar to the adrenomyeloneuropathy (AMN) type of X-ALD.[2]

If a male is diagnosed with X-ALD, it is likely that his mother is a carrier of the disease. However, about 5% of cases of X-ALD are caused by a new genetic change (de novo) in the individual. In these situations, the mother is not a carrier of the disease, and other family members are not at risk to have children with X-ALD. Therefore, when a male is diagnosed with X-ALD, it is important to determine if his mother is a carrier by testing her VLCFA levels or by genetic testing.[2]

If a woman is found to be a carrier of X-ALD, for each of her children there is a 50% chance that he or she will inherit the change in ABCD1. This means that for each son, there is a 50% chance that he will be affected with X-ALD. For each daughter, there is a 50% chance that she will be a carrier of the disease like her mother.

X-ALD shows a characteristic known as variable expressivity. This means that the exact symptoms of each person with X-ALD can differ, even within the same family. For example, some boys may have the childhood cerebral form of X-ALD, while other members of the same family may have the adrenal insufficiency-only type.[2] It is not known what causes variable expressivity of the disease to occur. The symptoms cannot be predicted by levels of VLCFA or by looking at the exact genetic change (mutation) in each individual.[2]
Last updated: 2/12/2018
X-linked adrenoleukodystrophy (X-ALD) is suspected when a doctor observes signs and symptoms of the disease. X-ALD should be considered as a possible cause of symptoms in four situations:[2]
  • Boys with attention deficit disorder (ADD) who also have signs of neurological problems
  • Young men with progressive trouble walking or coordinating movements
  • All males with adrenal insufficiency (Addison disease), even in the absence of other symptoms
  • Adult women with progressive muscle weakness or wasting
If a diagnosis of X-ALD is suspected, a blood test of very long-chain fatty acids will detect elevated levels in 99% of males. Genetic testing can be used to confirm the diagnosis. After diagnosis, a brain MRI can be completed to determine the extent of the disease. A brain MRI will be abnormal even if symptoms of the disease are not very severe.[2]
Last updated: 2/12/2018

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.
The treatment for X-linked adrenoleukodystrophy (X-ALD) depends on  the signs and symptoms present in each person and may include:[2][5]
  • Corticosteroids in case of  adrenal insufficiency, which are used to normalize hormone levels.
  • Physical therapy that may be helpful for men with the adrenomyeloneuropathy (AMN) form of the disease. 
  • Bone marrow transplant, which is only recommended for boys who have brain involvement showed by brain MRI, but who have only minimal neurological or psychological findings, and who have normal clinical neurologic examination.  This treatment have many risks and it is not recommended in cases of severe neurologic symptom.
  • Lorenzo’s oil, recommended for boys who do not yet have symptoms of X-ALD.[5] However, this treatment is experimental, and the treatment's exact benefit has not been definitively shown, but it may slow down the progression of the disease.
Clinical trials investigating treatment with gene therapy are currently underway and have shown some preliminary success.[2][6]
Last updated: 2/12/2018
The long-term outlook for people affected by X-linked adrenoleukodystrophy (X-ALD) depends on the exact type of the disease that each person has. The childhood cerebral form of the disease is progressive. Boys with this form of the disease often pass away within a few years of beginning to show symptoms.[2] The other forms of X-ALD are less severe. The disease for these individuals may be slowly progressive, or it may not affect a person’s lifespan at all.[2]

It is important to remember that the exact signs and symptoms of a person with X-ALD cannot be predicted by the signs and symptoms of other members of the family. Therefore, the long-term outlook for individuals who have X-ALD within the same family can be very different.[2]
Last updated: 2/12/2018

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to X-linked adrenoleukodystrophy . Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

Patient Registry

  • A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with X-linked adrenoleukodystrophy . The type of data collected can vary from registry to registry and is based on the goals and purpose of that registry. Some registries collect contact information while others collect more detailed medical information. Learn more about registries.

    Registries for X-linked adrenoleukodystrophy :
    Myelin Disorders Bioregistry Project
     

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

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

  • Genetics Home Reference (GHR) contains information on X-linked adrenoleukodystrophy . This website is maintained by the National Library of Medicine.
  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • The National Institute of Neurological Disorders and Stroke (NINDS) collects and disseminates research information related to neurological disorders. Click on the link to view information on this topic.
  • 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.

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.
  • 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 X-linked adrenoleukodystrophy . Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. X-linked adrenoleukodystrophy. Genetics Home Reference (GHR). July 2013; https://ghr.nlm.nih.gov/condition/x-linked-adrenoleukodystrophy.
  2. Steinberg SJ, Moser AB, and Raymond GV. X-linked Adrenoleukodystrophy. GeneReviews. April 9, 2015; http://www.ncbi.nlm.nih.gov/books/NBK1315/.
  3. Adrenoleukodystrophy (ALD). Kennedy Krieger Institute. http://www.kennedykrieger.org/patient-care/diagnoses-disorders/adrenoleukodystrophy-ald.
  4. Haldeman-Englert C. Adrenoleukodystrophy. MedlinePlus. October 27, 2015; http://www.nlm.nih.gov/medlineplus/ency/article/001182.htm.
  5. Adrenoleukodystrophy Information Page. National Disorders of Neurological Disorders and Stroke. https://www.ninds.nih.gov/Disorders/All-Disorders/Adrenoleukodystrophy-Information-Page. Accessed 11/1/2017.
  6. Eichler F, Duncan C, Musolino PL, Orchard PJ, de Oliveira S, Thrasher AJ, Armant M, Dansereau C, Lund TC, Miller WP, Raymond GV, Sankar R, Shah AJ, Sevin C, Gaspar HB, Gissen P, Amartino H, Bratkovic D, Smith NJC, Parker AM, Shamir E, O’Meara T, Davidson D, Aubourg P, and Williams DA. Hematopoietic Stem-Cell Gene Therapy for Cerebral Adrenoleukodystrophy. The New England Journal of Medicine. 2017; 377:1630-1638. http://www.nejm.org/doi/10.1056/NEJMoa1700554#t=articleTop.