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X-linked adrenoleukodystrophy

(X-linked • uh-DREE-noh-loo-koh-DI-struh-fee)

General Condition Information

Other Names

  • Adrenoleukodystrophy
  • X-Adrenoleukodystrophy
  • X-linked adrenoleukodystrophy, childhood onset
  • X-linked adrenyleukodystrophy

Condition Type

Birth Prevalence

  • It is estimated that fewer than 200 babies are born with this condition each year in the United States.
  • It is more common and more severe in boys.
  • Visit GeneReviews to learn more about how often this condition occurs.

Screening Finding

Increased C26:0 lysophosphatidylcholine, or increased C26:0 lysophosphatidylcholine and one X-ALD-causing change in the ABCD1 gene

What is x-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is an inherited (genetic) condition that prevents the body from breaking down certain fats that are important in certain parts of the body like the brain, spinal cord, as well as the adrenal glands, which help produce certain hormones in the body.

The X-linked adrenoleukodystrophy protein (ALDP) is a transporter protein that brings a type of fat called very long-chain fatty acids (VLCFA) into peroxisomes to be processed. Peroxisomes are small areas inside your cells that perform important functions, including breaking down this type of fat.

In X-ALD, the protein ALDP is not made correctly, so these fats cannot enter peroxisomes to be processed. These VLCFA build up over time and damage the nervous system (including the brain and spinal cord) and the adrenal glands, which produce important hormones.

Damage caused by the buildup of VLCFA in the adrenal glands can prevent the adrenals from producing necessary hormones. This can make it harder to recover from infections or other stress. This damage, called adrenal insufficiency, is not ordinarily seen in babies but may develop as they get older. Adrenal insufficiency can be found with a blood test.

The VLCFA can also build up in the brain. About 35 percent of boys with this buildup develop the brain, or cerebral, form of X-ALD, which is the most severe. This condition usually occurs in boys 4 to 10 years old but can be earlier or later in life. There is also an adult form of the condition that affects the spinal cord, called adrenomyeloneuropathy (AMN). AMN is generally seen in young adults.

Newborn Screening and Follow-Up

Condition Details

Treatment and Management

It is important to talk to your health care provider about which treatment(s) are best for your baby. The goal of treatment is to prevent the health problems caused by this condition. 

Treatments may include the following:

  • Regular monitoring of the nervous system (using magnetic resonance imaging [MRI]) and of the adrenal gland (using special blood tests)
  • Hormone replacement therapy if the adrenal glands are not functioning well. This is usually a pill taken several times daily.
  • Stem cell transplantation, if the cerebral (brain) form of the condition is present
  • Medicines for certain symptoms (e.g., stiffness and seizures)
  • Physical therapy
  • Additionally, new and investigational therapies may be available through research based clinical trials.

Children who receive early and ongoing treatment for X-ALD can have better health outcomes than those who do not. Early stem cell transplantation can help prevent problems in children with nervous system symptoms. Treatment works best if it is given when changes are just beginning in the brain, before it becomes extensive and nervous system signs or symptoms start.

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