Adrenoleukodystrophy, ALD, is a genetic disorder connected to the X chromosome. It affects the nervous system and adrenal glands. Symptoms of ALD often include behavioral and cognitive changes. ALD affects males more than females. Treatment focuses on stopping or slowing the disease’s progression and improving symptoms.
Adrenoleukodystrophy (ALD) is one of a group of genetic disorders called leukodystrophies. ALD affects the nervous system and the adrenal glands.
ALD is a progressive disease. Treatments aim to slow the progression and improve people’s quality of life.
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A genetic disorder results from a mutation (change) in part of your DNA. DNA contains genetic building blocks — the instructions for how your body works.
People with ALD can’t break down high levels of fat molecules — specifically very-long-chain fatty acids (VLCFAs). As a result, VLCFAs build up in the brain, nervous system and adrenal cortex, the largest part of the adrenal gland.
Scientists aren’t exactly sure how the VLCFA buildup affects the body. But research suggests the accumulation causes inflammation that damages the myelin sheath. Myelin is the protective layer around nerve cells in the brain.
When myelin is damaged, nerve cells cannot send signals from the brain to the body. This causes problems with the body’s functions, including how you move and think.
People with ALD have shortages of some hormones because ALD also damages the adrenal glands. The adrenal glands sit on top of each kidney. They make hormones that affect male and female sex characteristics and your stress response.
ALD is a genetic condition. People can inherit ALD from one or both parents. It’s sometimes called X-linked ALD because it results from a problem with the X chromosome.
ALD is a rare disease, affecting around 1 in 15,000 people worldwide. It affects more males than females.
The cause of ALD is a mutation in a particular gene. Your genes are the instruction manual for creating proteins that have critical roles in how the body works. With a genetic mutation, the gene may create faulty protein.
With ALD, there’s a problem with the ABCD1 gene, which creates the ALDP protein. This protein helps break down VLCFAs. Because of the faulty protein, VLCFAs accumulate in the body’s tissues.
The most common forms of ALD are:
Less-common types of ALD include:
ALD symptoms often appear between the ages of 3 and 10, though they can start later in life. The childhood form of ALD is the most severe.
Each type has its own symptoms. People often have both neurological and hormonal symptoms.
Early symptoms include:
As the disease progresses, symptoms include:
Eventually, children lose most of their neurological abilities. They lose sight, hearing and voluntary movements. As the disease progresses, children end up in a vegetative state. They often pass away within two to three years of the neurological symptoms’ starting.
Addison’s disease symptoms:
Symptoms of adrenal insufficiency include:
ALD is an X-linked genetic disorder. It results from a mutated gene on the X chromosome.
Females, who have two X chromosomes, can be carriers of the disorder. One of the X chromosomes is “shut off.” That means the genes on that chromosome aren’t active.
Females usually don’t have symptoms because the “shut-off” X chromosome carries the mutated gene. Females who have symptoms usually get a milder form that develops during adulthood.
Males have only one X chromosome. The mutated X chromosome can cause more severe ALD because males lack the protective effect of the extra X chromosome.
Some infants are diagnosed at birth during newborn screening. Newborn screening tests babies for certain diseases. About a dozen states screen for ALD during newborn screening in the hospital. More often, parents or providers notice symptoms in a child’s early years.
People with the adult form may receive a diagnosis after seeing their provider about symptoms.
Parents and providers should consider a possible ALD diagnosis when a:
· Boy with ADD or ADHD also has signs of a neurological disorder.
· Young male has walking or movement problems that are getting worse.
· Male of any age has Addison’s disease, even without other symptoms or problems.
· Female adult has worsening muscle weakness.
Healthcare providers evaluate your child’s medical and family history. If the provider suspects ALD, your child may have:
If the genetic test confirms ALD, your provider may recommend other family members receive genetic testing.
ALD has no cure at this time. Treatment focuses on slowing the disease’s progression and improving symptoms.
Treatment options depend on the type of ALD and symptoms. Treatments include:
Other supportive treatments include:
Investigational therapies include:
Can ALD be prevented?
There is no known way to prevent ALD. If a family member has ALD, follow your provider’s recommendation for genetic testing and counseling.
The prognosis for people with ALD depends on the type. Children with childhood cerebral X-ALD generally have a poor prognosis. Unless they receive a stem cell transplant early in the disease, their neurological function deteriorates. In many cases, children pass away within a few years after symptoms begin.
For people with adult-onset AMN, the disease can progress over many decades.
Early intervention may offer the best chance for successful treatment. If you notice signs in your child, including behavioral or cognitive changes, talk to your healthcare provider. Also talk to your provider if your child seems to lose abilities they once had.
Your child’s care team should include:
If your child receives a diagnosis of ALD, ask your provider:
A note from Cleveland Clinic
ALD is a genetic disorder that affects the nervous system and adrenal glands. Symptoms often start in early childhood, when children lose skills they previously had. If your child shows behavioral changes or regresses in other areas, talk to your healthcare provider. The earlier treatment for ALD starts, the better the chances of slowing the disease. Several ALD treatments are available, including stem cell transplant, medications and supportive therapies. Your care team will talk to you about your child’s specific condition and outlook.
Last reviewed by a Cleveland Clinic medical professional on 05/17/2021.
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