AdrenoleukodystrophyDefinition: Adrenoleukodystrophy describes several closely related inherited disorders that disrupt the breakdown (metabolism ) of certain fats (very-long-chain fatty acids).
Alternative Names: Adrenoleukodystrophy; Adrenomyeloneuropathy; Childhood cerebral adrenoleukodystrophy; ALD; Schilder-Addison Complex
Causes, incidence, and risk factors: Adrenoleukodystrophy is passed down from parents to their children as an X-linked genetic trait . It therefore affects mostly males, although some women who are carriers can have milder forms of the disease. It affects approximately 1 in 20,000 people from all races.
The condition results in the buildup of very-long-chain fatty acids in the nervous system, adrenal gland, and testes, which disrupts normal activity. There are three major categories of disease:
- Childhood cerebral form -- appears in mid-childhood (at ages 4 - 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
Symptoms: Childhood cerebral type:
- Changes in muscle tone, especially muscle spasms and spasticity
-
Crossed eyes (strabismus)
- Decreased understanding of verbal communication (aphasia)
- Deterioration of handwriting
- Difficulty at school
- Difficulty understanding spoken material
- Hearing loss
-
Hyperactivity
- Worsening nervous system deterioration
- Coma
- Decreased fine motor control
- Paralysis
- Seizures
- Swallowing difficulties
- Visual impairment or blindness
Adrenomyelopathy:
- Difficulty controlling urination
- Possible worsening muscle weakness or leg stiffness
- Problems with thinking speed and visual memory
Adrenal gland failure (Addison type):
- Coma
- Decreased appetite
- Increased skin color (pigmentation)
- Loss of weight, muscle mass (wasting)
- Muscle weakness
- Vomiting
Signs and tests:
- Blood levels
- Chromosome study to look for changes (mutations) in the ABCD1 gene
- MRI of the head
Treatment: Adrenal dysfunction is treated with steroids (such as cortisol).
A specific treatment for X-linked adrenoleukodystrophy is not available, but eating a diet low in very-long-chain fatty acids and taking special oils can lower the blood levels of very-long-chain fatty acids.
These oils are called Lorenzo's oil, after the son of the family who discovered the treatment. This treatment is being tested for X-linked adrenoleukodystrophy, but it does not cure the disease and may not help all patients.
Bone marrow transplant is also being tested as an experimental treatment.
Expectations (prognosis): The childhood form of X-linked adrenoleukodystrophy is a progressive disease that leads to a long-term coma (vegetative state) about 2 years after neurological 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.
Complications:
- Adrenal crisis
- Vegetative state (long-term coma)
Calling your health care provider: Call your health care provider if:
- Your child develops symptoms of X-linked adrenoleukodystrophy
- Your child has X-linked adrenoleukodystrophy and is getting worse
Prevention: Genetic counseling is recommended for prospective parents with a family history of X-linked adrenoleukodystrophy. Female carriers can be diagnosed 85% of the time using a very-long-chain fatty acid test and a DNA probe study done by specialized laboratories.
Prenatal diagnosis of X-linked adrenoleukodystrophy is also available. It is done by evaluating cells from chorionic villus sampling or amniocentesis .
References: Johnston MV. Neurodegenerative disorders of childhood. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 599.
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