What Is ALS?

Who gets ALS?

An estimated 5,000 people are newly diagnosed with ALS each year in the United States. Even though it’s not clear what causes ALS, certain people may be more likely to get it.

A small proportion of the people who get ALS — about 1 in 10 — were born with a gene mutation that caused the disease. Their children run a 50-50 chance of having this mutation, too. In most cases, just inheriting the gene from one parent is enough to ensure that a person will develop what’s called familial, or genetic, ALS.

About 25 to 40 percent of people with familial ALS have defects in a gene called C9orf72. Another 12 to 20 percent of familial cases have ALS due to a defect in a gene called SOD1. People who have C9orf72, the most common inherited gene mutation for ALS, may be at higher risk for a form of dementia called frontotemporal dementia (FTD). The same gene mutation in a family can cause ALS, FTD or both. “You can have a sister with ALS and a brother with FTD,” Rothstein says. “We don’t think of ALS as a dementia disease, but sometimes you can have a very severe dementia with it, which is usually because of that gene mutation.”

The vast majority of people with ALS — 9 in 10 — did not inherit a gene from a family member and have no family history of the disease. They have what’s called sporadic ALS. Age and, to a certain degree, sex are the only known risk factors for sporadic ALS. The age at which the disease is most often diagnosed is between the 50s and mid-70s. Familial ALS may develop much earlier, around age 45 or younger.

Before age 65, ALS is a little more common in men than in women. After age 70, rates are the same for both sexes.

Aside from these known risk factors, smokers may be more likely to develop ALS, as are people who’ve been exposed to environmental toxins, such as lead or certain chemicals, research suggests. For some reason, perhaps due to toxic exposures, people who have served in the military seem to be at higher risk.

Is there treatment for ALS?

There’s no cure for ALS. People who have it will eventually die from the condition. Three medications approved by the U.S. Food and Drug Administration may slow the progression of the disease. Additional medications are used to treat symptoms and prevent complications to make patients comfortable and live as well as possible with ALS.

Kuldip Dave of the ALS Foundation recommends patients receive treatment at a multidisciplinary clinic “to interact with a team of health care professionals, not only a neurologist or ALS specialist, but also a physical therapist, pulmonologist, respiratory therapist and nurse coordinator.” Speech therapists, dietitians and social workers may also be part of the team. “Multiple publications show that people with ALS [who attend] a multidisciplinary clinic have at least a 10- to 18-month increased survival,” he says.

What can you expect with ALS?

ALS eventually weakens the muscles used for mobility, breathing, speaking and swallowing. You may need technology, devices and eventually professional care to help with each of these. For some people, ALS can progress to this point very quickly, and for others it can take years. Doctors typically won’t be able to let you know how fast the disease will progress.

No matter how quickly or slowly, ALS does progress over time. Eventually, people with this condition need more care than a spouse or adult child alone can provide. “Home caregivers are very common for ALS patients somewhere in the course of the disease, and, of course, at the very end, there can be hospice,” Rothstein says.

A variety of assistive devices are available to help people with ALS move around their homes, speak, breathe and carry out other tasks of daily living as the disease progresses. Assistive technology is also an area of active research in ALS to bring more effective tools to patients.

Though currently available drugs may slow the progress of ALS by a few months, they won’t cure it, halt it or reverse the damage. But scientific understanding of ALS — expanded in part by the Ice Bucket Challenge — has advanced in recent years.

For one, researchers have made some headway in treating familial ALS. There are around 40 known genes that cause genetic ALS. In 2023, the Food and Drug Administration approved Qalsody (tofersen), the first drug to target one of those genes, SOD1, believed to be mutated in 1 to 2 percent of people with ALS.

In a clinical trial, when people with ALS due to SOD1 mutations received Qalsody intraspinal injections (three loading doses every two weeks followed by five monthly maintenance doses), levels of a protein called neurofilament-light (NfL) that is elevated in people with ALS began to drop. The drug received accelerated approval because of the need for effective therapies, and the reduction in NfL is considered a predictor of patient benefit. Researchers will continue to study the drug to see if it actually has an effect on the progress and symptoms of the disease.

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“The important thing is that they were able to develop a therapy that went straight for that gene and repaired it,” Dave says. He’s optimistic that the same approach can be used to mute the effects of other genes gone awry in ALS: “Now we have the formula to do this for the other 39 genes.”

NfL is the focus of other ALS research, beyond those people with familial ALS. Researchers are getting closer to understanding how to use this protein as a blood biomarker for the disease in all patients. This could lead to earlier detection and, potentially, drugs that target the protein directly as a way to stop the disease.

The last 10 years of extra support for ALS research have led to a larger-than-ever diversity of research. More than 35 clinical trials are recruiting U.S. patients affected with ALS to test new therapies. Promising work is underway in the following areas:

• Repurposing anti-inflammatory drugs. It’s known that inflammation underpins neurodegenerative diseases, including ALS. A growing number of drug companies are taking an interest in ALS and testing the impact of existing anti-inflammatory drugs for people with ALS.
• Correcting defects in TDP-43. This protein in the nuclei of cells in the central nervous system plays a crucial role in their function. But in ALS, a specific defect puts TDP-43 outside the nucleus of motor neurons. Researchers are testing a drug that moves the protein back in place, and they are now in the early days of developing ALS treatments based on this concept.
• Using brain-computer interfaces (BCI). An implantable device in the brain would allow people with ALS to use their thoughts to control computers, equipment and devices such as wheelchairs and breathing and speech assistance.

“For a rare disease like ALS, having that many opportunities is a good thing,” Dave says. “We don’t know where our next home run is going to come from. The fact that we have multiple ways to go after this disease is really exciting.”​​​