ALS affects roughly 1 in every 400 people who die in the United States, making it rare but not unknown

ALS is a rare disease, meaning it does not affect large portions of the population. At any given time, between 14,000 and 15,000 people in the United States are living with ALS. Each year, doctors diagnose about 5,000 new cases and roughly 5,000 people die from the disease. These numbers have stayed relatively stable for decades, though some research suggests the rate may be rising slightly in certain age groups.

The rarity of ALS means many doctors see only a handful of cases in their careers. It also means that if you or a family member has been diagnosed, you are part of a small group—which can feel isolating but also means there are established networks of specialists and support organizations focused specifically on this disease.

Key Takeaways

  • About 5,000 Americans receive a new ALS diagnosis each year, and roughly 14,000 to 15,000 people are living with the disease at any given time.
  • ALS can develop at any age but is most common in people between 55 and 75 years old.
  • Men are diagnosed with ALS slightly more often than women, though the reason is not fully understood.
  • Most ALS cases appear randomly with no family history, but about 5 to 10 percent of cases run in families.
  • Geographic location, race, and ethnicity do not significantly change the risk of developing ALS.

Who typically develops ALS

ALS most commonly appears in people aged 55 to 75, though it can strike at any age—including children, though this is extremely rare. The average age at diagnosis is around 63 years old. People in their 40s and 50s do develop ALS, as do people in their 80s and beyond, but the disease becomes more common as people age.

Men are diagnosed with ALS about 1.5 times more often than women. Scientists do not yet know why this difference exists. It is not because men are exposed to something women are not, and it is not because women are protected by something in their biology—the reason remains unclear and is an active area of research.

Family history and inherited ALS

About 90 percent of ALS cases appear to occur randomly, with no family history of the disease. These are called sporadic ALS cases. A person with sporadic ALS did not inherit it from a parent and will not automatically pass it to their children, though researchers continue to study whether genetic factors play a role even in cases without a clear family pattern.

The remaining 5 to 10 percent of cases are familial ALS, meaning the disease runs in the family. If one of your parents, siblings, or children has ALS, your own risk is higher than the general population—though still relatively low. Familial ALS follows an autosomal dominant pattern in most cases, which means you need to inherit only one copy of the gene mutation from one parent to develop the disease. A parent with familial ALS has roughly a 50 percent chance of passing the mutation to each child.

Genetic testing can identify whether you carry a mutation linked to familial ALS, but a negative test does not rule out the disease entirely. If you have a family history of ALS, a genetic counselor can explain what testing might tell you and what it would mean for your health decisions.

Geographic and demographic patterns

ALS occurs worldwide and affects people of all races and ethnicities. There is no geographic "hotspot" where ALS is dramatically more common, and no ethnic group is protected from the disease. Some studies have found small variations in diagnosis rates between regions or populations, but these differences are thought to reflect differences in healthcare access and diagnostic practices rather than true differences in disease occurrence.

Certain occupations have been studied for possible links to ALS—including military service, farming, and jobs involving exposure to heavy metals or pesticides. Research has not established a clear causal link, though some studies suggest military veterans may have a slightly elevated risk. The reason, if one exists, is not yet known.

Why ALS is considered rare

A disease is classified as rare in the United States when it affects fewer than 200,000 people at any one time. With roughly 14,000 to 15,000 people living with ALS, the disease falls well below that threshold. This classification matters because it affects how much research funding the disease receives and what incentives pharmaceutical companies have to develop treatments.

The rarity of ALS also means that many primary care doctors and general neurologists may see only one or two cases in their entire career. This is one reason why getting to an ALS specialist—a neurologist with specific training in motor neuron diseases—can make a difference in how quickly you receive a diagnosis and how well your care is coordinated.

What the numbers mean for diagnosis and research

Because ALS is rare, doctors sometimes take longer to diagnose it. Symptoms can resemble other conditions, and a doctor who has never seen ALS may not immediately recognize the pattern. If you have been experiencing progressive weakness or muscle changes and your primary care doctor is uncertain, asking for a referral to a neurologist or ALS specialist can speed up the diagnostic process.

The rarity of ALS also shapes research. Large drug trials are harder to conduct when the disease affects relatively few people, which is why some ALS research relies on smaller studies or on data collected from patient registries. Organizations like the ALS Association maintain databases of people willing to participate in research, which helps scientists understand the disease better and test new treatments.

Frequently Asked Questions

Is ALS becoming more common?

Some recent studies suggest the rate of ALS diagnosis may be rising slightly, particularly in people over 60. The reasons are not clear—it could reflect better diagnosis, aging populations, or actual changes in disease occurrence. Researchers continue to monitor these trends.

If my parent has ALS, will I definitely get it?

Not necessarily. If your parent has familial ALS, you have roughly a 50 percent chance of inheriting the gene mutation. Even if you inherit the mutation, the disease does not always develop, and if it does, the age of onset can vary widely. Genetic counseling can help you understand your specific situation.

Can children get ALS?

Yes, though it is extremely rare. Juvenile ALS, which appears before age 25, accounts for less than 5 percent of all ALS cases. Children with familial ALS are more likely to develop the disease than children without a family history, but sporadic ALS in children is exceptionally uncommon.

Does where I live affect my risk of ALS?

No. ALS occurs in all geographic regions and all countries. Some areas may report slightly different diagnosis rates, but this reflects differences in healthcare systems and access to specialists rather than true differences in disease risk.

Why do more men get ALS than women?

The reason is unknown. It is not because men are exposed to something harmful that women avoid, and it is not because women have biological protection. Scientists are actively researching this difference, but no clear explanation has emerged yet.