What is Adrenoleukodystrophy?
Adrenoleukodystrophy (ALD) is one of a group of genetic disorders called the leukodystrophies that cause damage to the myelin sheath, an insulating membrane
that surrounds nerve cells in the brain. People with ALD accumulate high levels
of saturated, very long chain fatty acids (VLCFA) in the brain and adrenal
cortex because they do not produce the enzyme that breaks down these fatty acids
in the normal manner. The loss of myelin and the progressive dysfunction of the
adrenal gland are the primary characteristics of ALD. ALD has two subtypes. The
most common is the X-linked form (X-ALD), which involves an abnormal gene
located on the X-chromosome. Women have two X-chromosomes and are the carriers
of the disease, but since men only have one X-chromosome and lack the protective
effect of the extra X-chromosome, they are more severely affected. Onset of X-ALD
can occur in childhood or in adulthood. The childhood form is the most severe,
with onset between ages 4 and 10. The most common symptoms are usually
behavioral changes such as abnormal withdrawal or aggression, poor memory, and
poor school performance. Other symptoms include visual loss, learning
disabilities, seizures, poorly articulated speech, difficulty swallowing,
deafness, disturbances of gait and coordination, fatigue, intermittent vomiting,
increased skin pigmentation, and progressive dementia. In the milder adult-onset
form, which typically begins between ages 21 and 35, symptoms may include
progressive stiffness, weakness or paralysis of the lower limbs, and ataxia.
Although adult-onset ALD progresses more slowly than the classic childhood form,
it can also result in deterioration of brain function. A mild form of ALD is
occasionally seen in women who are carriers of the disorder. Symptoms include
progressive stiffness, weakness or paralysis of the lower limbs, ataxia,
excessive muscle tone, mild peripheral neuropathy, and urinary problems.
Is there any treatment?
Adrenal function must be tested periodically in all patients with ALD.
Treatment with adrenal hormones can be lifesaving. Symptomatic and supportive
treatments for ALD include physical therapy, psychological support, and special
education. Recent evidence suggests that a mixture of oleic acid and erucic
acid, known as "Lorenzo's Oil," administered to boys with X-ALD can reduce or
delay the appearance of symptoms. Bone marrow transplants can provide long-term
benefit to boys who have early evidence of X-ALD, but the procedure carries risk
of mortality and morbidity and is not recommended for those whose symptoms are
already severe or who have the adult-onset or neonatal forms. Oral
administration of docosahexanoic acid (DHA) may help infants and children with
neonatal ALD.
What is the prognosis?
Prognosis for patients with ALD is generally poor due to progressive
neurological deterioration. Death usually occurs within 1 to 10 years after the
onset of symptoms.
What research is being done?
The NINDS supports research on genetic disorders such as ALD. The aim of this
research is to find ways to prevent, treat, and cure these disorders. Intensive
basic research has proposed two new approaches, 4-phenylbutyrate and lovastatin,
which could potentially lower levels of VLCFA in the brain. Therapeutic trials
for both agents are planned
Organizations
National Organization for Rare Disorders (NORD)
P.O. Box 1968
55 Kenosia Avenue
Danbury, CT 06813-1968
orphan@rarediseases.org
www.rarediseases.org
Tel: 203.744.0100 Voice Mail 800.999.NORD (6673)
Fax: 203.798.2291
National Tay-Sachs and Allied Diseases Association
2001 Beacon Street, Suite 204
Boston, MA 02135
info@ntsad.org
www.ntsad.org
Tel: 800.90.NTSAD (906.8723)
Fax: 617.277.0134
United Leukodystrophy Foundation
2304 Highland Drive
Sycamore, IL 60178
office@ulf.org
www.ulf.org
Tel: 815.895.3211 800.728.5483
Fax: 815.895.2432
Myelin Project
1400 Wallace Boulevard, Suite 258
Amarillo, TX 79106
margaret.weis@myelin.org
www.myelin.org
Tel: 806.356.4693 800.869.3546
Fax: 806.356.4694
Source: National Institutes of Health; National Institute of Neurological Disorders and Stroke
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