Adrenoleukodystrophy

Adrenoleukodystrophy (ALD) describes several closely related disorders that disrupt the breakdown of certain fats. These disorders are often passed down (inherited) in families.

Causes

ALD is usually passed down from parent to child as an X-linked genetic trait. It affects mostly males. Some women who are carriers can have milder forms of the disease. It affects about 1 in 20,000 people from all races.

X-linked genetic trait

Genetics is the study of heredity, the process of a parent passing certain genes to their children. A person's appearance -- height, hair color, ski...

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Some cases of ALD occur when the gene changes on its own. This is called sporadic and is not inherited.

The condition results in the buildup of very-long-chain fatty acids in the nervous system, adrenal gland, and testes. This disrupts normal activity in these parts of the body.

There are three major categories of disease:

• Childhood cerebral form -- appears in mid-childhood (at ages 4 to 8)
• Adrenomyelopathy -- occurs in men in their 20s or later in life
• Impaired adrenal gland function (called Addison disease or Addison-like phenotype) -- adrenal gland does not produce enough steroid hormones

  Addison disease

  Addison disease is a disorder that causes the adrenal glands to not produce enough hormones.

  

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Symptoms

Childhood cerebral type symptoms include:

• Changes in muscle tone, especially muscle spasms and uncontrolled movements
• Crossed eyes

  Crossed eyes

  Strabismus is a disorder in which both eyes do not line up in the same direction. Therefore, they do not look at the same object at the same time. ...

  

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• Handwriting that gets worse
• Difficulty at school
• Difficulty understanding what people are saying
• Hearing loss
• Hyperactivity

  Hyperactivity

  Hyperactivity means having increased movement, impulsive actions, a shorter attention span, and being easily distracted.

  

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• Worsening nervous system damage, including coma, decreased fine motor control, and paralysis
• Seizures

  Seizures

  A seizure is the physical changes in behavior that occurs during an episode of specific types of abnormal electrical activity in the brain. The term ...

  

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• Swallowing difficulties
• Visual impairment or blindness

Adrenomyelopathy symptoms include:

• Difficulty controlling urination
• Possible worsening muscle weakness or leg stiffness
• Problems with thinking speed and visual memory

Adrenal gland failure (Addison type) symptoms include:

• Coma
• Decreased appetite
• Increased skin color
• Loss of weight and muscle mass (wasting)
• Muscle weakness
• Vomiting

Exams and Tests

In most states, children will be screened for ALD as part of newborn screening tests. This is done with a heel stick to draw blood (as part of the routine screenings done on newborns). Newborn screening does not diagnose the condition, but it can help lead to early testing and diagnosis.

Tests for this condition include:

• Blood levels of very long chain fatty acids and hormones that are produced by the adrenal gland
• Chromosome study to look for changes in the ABCD1 gene that may make the person more likely to develop a disease

  Chromosome

  Chromosomes are structures found in the center (nucleus) of cells that carry long pieces of DNA. DNA is the material that holds genes. It is the bu...

  

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• MRI of the head

  MRI of the head

  A head MRI (magnetic resonance imaging) is an imaging test that uses powerful magnets and radio waves to create pictures of the brain and surrounding...

  

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• Skin biopsy

  Skin biopsy

  A skin lesion biopsy is when a small amount of skin is removed so it can be examined under a microscope. The skin is tested to look for skin conditi...

  

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Treatment

Adrenal dysfunction may be treated with steroids (such as cortisol) if the adrenal gland is not producing enough hormones.

A specific treatment for X-linked ALD is not available. A bone marrow transplant may stop worsening of the condition.

Supportive care and careful monitoring of impaired adrenal gland function may help in improving comfort and quality of life.

Support Groups

More information and support for people with ALD and their families can be found at:

• National Organization for Rare Disorders -- rarediseases.org/rare-diseases/adrenoleukodystrophy/
• NIH Genetic and Rare Diseases Information Center -- rarediseases.info.nih.gov/diseases/5758/x-linked-adrenoleukodystrophy

Outlook (Prognosis)

The childhood form of X-linked ALD is a progressive disease. It leads to a long-term coma (vegetative state) about 2 years after nervous system symptoms develop. The child can live in this condition for as long as 10 years until death occurs.

The other forms of this disease are milder.

Possible Complications

These complications can occur:

• Adrenal crisis
• Vegetative state

When to Contact a Medical Professional

Contact your health care provider if:

• Your child develops symptoms of X-linked ALD
• Your child has X-linked ALD and is getting worse

Prevention

Genetic counseling is recommended for couples with a family history of X-linked ALD. Mothers of affected sons have an 85% chance of being a carrier for this condition.

Prenatal diagnosis of X-linked ALD is also available. It is done by testing cells from chorionic villus sampling or amniocentesis. These tests look for either a known genetic change in the family or for very long chain fatty acid levels.