Juvenile ALS is a very rare type of ALS that begins when a person is under age 25. Many cases of juvenile ALS have a genetic cause. The rate of progression can also vary widely. There’s no cure for juvenile ALS.

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Amyotrophic lateral sclerosis (ALS) is a neurological disease where motor neurons, which are nerve cells that control muscle movement, die over time. This leads to muscle weakness, wasting, and lessened ability to initiate or control movements.

Most of the time, ALS affects adults 55–75 years old. However, in rare cases, ALS symptoms can develop in children or adolescents. This is called juvenile ALS.

Keep reading as we dive deeper into juvenile ALS, what causes it, and how doctors diagnose and treat it.

Here’s more detailed information about ALS.

Some factors make juvenile ALS different from adult-onset ALS. Let’s explore these now.


Juvenile ALS has a large genetic component. That means that many cases, an estimated 40%, are linked to specific genetic mutations.

Genetics plays a reduced role in adult-onset ALS. Only 5–10% of adult-onset ALS cases occur in two or more family members.


The outlook for people with juvenile ALS varies greatly, often based on the type of mutation that’s present. Some people may have a slower disease course, while others may have a more aggressive one.

Adult-onset ALS is generally aggressive. The median survival time after diagnosis is 3–5 years.

The symptoms of juvenile ALS vary from person to person. For people with a known genetic cause of juvenile ALS, symptoms can depend on the gene mutation.

The symptoms of juvenile ALS begin before age 25. Some of the potential symptoms of juvenile ALS include:

Juvenile ALS is a progressive neurological disease. That means it worsens over time.

As juvenile ALS progresses, a person is increasingly unable to do physical tasks, like walking or standing, getting out of bed, or using their arms and hands.

Many people with juvenile ALS die due to respiratory failure when the condition begins to affect their respiratory muscles.

The symptoms of juvenile ALS occur due to the degeneration of motor neurons. These neurons control muscle movement in the body, so as they die, movement becomes gradually impaired.

In some situations, the cause of juvenile ALS is unknown. However, sometimes, the condition can be linked to a known genetic mutation.

Genetic mutations leading to juvenile ALS may occur for the first time in a person who develops the condition. They may also be inherited from one or both parents.

A 2021 review of research notes that the following genes are most commonly associated with juvenile ALS:

  • ALS2
  • FUS
  • SETX

Other genes that have been linked with juvenile ALS include but aren’t limited to:

  • SPG11
  • SPTLC1
  • SOD1
  • UBQLN2

There isn’t one test doctors can use to diagnose juvenile ALS. Instead, your doctor uses your medical history and the results of a physical exam, neurological evaluation, and other tests to help them make a diagnosis.

Your doctor starts by taking your full medical history and doing a physical exam. The physical exam also includes a neurological evaluation to check things like your:

If your doctor suspects a motor neuron disorder, they will order other tests, such as:

There’s no cure or specific treatment for juvenile ALS. Instead, care focuses on managing symptoms, promoting independence, and improving quality of life.

The therapies that may help treat juvenile ALS include:

If your doctor diagnoses juvenile ALS, they may recommend that you participate in a clinical trial. Clinical trials test new or updated treatments to see whether they’re safe and effective.

You can find out whether there are clinical trials for juvenile ALS in your area by searching ClinicalTrials.gov. Your doctor may also be able to give you information on clinical trials you’re eligible for.

Juvenile ALS is very rare. As such, we’re still learning more about its causes and risk factors.

That said, some cases of juvenile ALS can be due to inherited gene mutations. If someone in your family has developed juvenile ALS, you may have an increased risk for it.

The symptoms of juvenile ALS get worse as it progresses. People with juvenile ALS may become unable to move anytime between 12 and 50 years old, depending on the rate of progression.

The rate of progression can vary between people. It’s often based on the genetics of their ALS. Many people with juvenile ALS have a slower progression rate and prolonged survival than people with adult-onset ALS.

However, juvenile ALS linked to mutations in the FUS gene tends to be more aggressive. This type of juvenile ALS has been observed to lead to death due to failure of respiratory muscles within 1–2 years.

How common is juvenile ALS?

Juvenile ALS is very rare. Researchers estimate its incidence is around 1 case per 1 million people.

How is juvenile ALS inherited?

When juvenile ALS is inherited, it can be either autosomal dominant or autosomal recessive. The exact inheritance pattern depends on the specific mutations involved.

Autosomal dominant means you only need one copy of a mutated gene to develop the condition.

Autosomal recessive means you need two copies of a mutated gene, one from each parent, to develop juvenile ALS.

Can juvenile ALS be prevented?

There’s currently no known way to prevent juvenile ALS.

However, if ALS runs in your family, consulting with a genetic counselor can help you understand your risk of passing mutations associated with juvenile ALS onto your children.

Juvenile ALS is a type of ALS that affects children and adolescents. Symptoms occur before a person turns 25.

Unlike adult-onset ALS, many cases of juvenile ALS have a known genetic component. Progression also varies from slow to aggressive. This contrasts with adult-onset ALS, which typically follows an aggressive course.

There’s no cure for juvenile ALS. Treatment aims to manage symptoms while boosting independence and quality of life.

Because the progression of juvenile ALS can vary widely, talk with your doctor to get a better idea of your individual outlook.