ALS Causes and Risk Factors

After being diagnosed with ALS, many people wonder: “Why did this happen to me?” There is no simple answer, because the exact cause of ALS is still unknown. 

While the cause is not fully understood, researchers have linked ALS risk to several factors, including genetics, environmental exposures and family history. In some cases, ALS develops with no clear reason at all. At Banner Brain & Spine, we’re here to help you and your loved ones understand ALS, explore possible risk factors and find the care and resources you need.

What is ALS?

ALS (amyotrophic lateral sclerosis), sometimes known as Lou Gehrig’s disease, is a neurodegenerative disease that damages motor neurons, the nerve cells that control muscle movement. Over time, these cells die, leading to muscle weakness and eventual problems with speaking, swallowing and breathing. 

While ALS is a disease of the nervous system, it is different from other conditions like multiple sclerosis (MS). ALS directly damages motor neurons, causing a steady decline in muscle control. 

Learn more about the differences between these two nervous system diseases. 

What causes ALS?

There is probably not one single cause of ALS. Instead, experts believe it results from a combination of genetic, biological, environmental and other factors that increase a person’s risk. These influences may affect how nerve cells function and respond to stress, eventually leading to nerve damage and muscle weakness. 

Genetics and ALS

For 90% of people with ALS, there is no clear genetic link to the disease. This is considered sporadic ALS (sALS). However, about 10% of people with ALS inherit a gene from a family member, a condition known as hereditary or familial ALS.   

If a parent carries a gene mutation linked to ALS, there is a chance it can be passed down to their children. Several gene mutations have been connected to the disease, including changes in the SOD1, C9orf72, TARDBP and FUS genes.

Genetic counseling can help patients learn more about possible genetic connections.

Environmental and lifestyle factors

Certain environmental exposures and lifestyle choices may raise the risk of ALS, although more research is still needed. 

• Military service: Military service members have higher rates of ALS than the general population. Researchers are investigating causes including physical stress, chemical exposure or injuries. 

Biological factors

Certain biological traits may also increase ALS risk:

• Age: Most people are diagnosed between the ages of 40 and 70. The risk increases as we age. 
• Sex: Men are slightly more likely than women to develop ALS, although the difference becomes smaller with age. 
• Nerve cell changes: Researchers are studying how abnormal protein build-up, chemical imbalances, immune system problems and cell stress may damage motor neurons and lead to ALS.

Can ALS be prevented?

There is no known way to prevent ALS. Researchers are studying genetics, environment and biology to understand what triggers it. 

What should you do if you are at risk?

If you have a family history of ALS or notice early signs such as unexplained muscle weakness or twitching, talk to your health care provider. 

Your provider may recommend:

• A neurological exam to check muscle strength, reflexes and coordination
• Genetic counseling and testing if ALS runs in your family
• Monitoring symptoms over time to watch for progression

Even if ALS cannot be prevented, supportive care and planning can make a difference in your quality of life. 

Learn more about the treatment and care of ALS.

The Banner Health difference

An ALS diagnosis can feel overwhelming, but you don’t have to face it alone. Banner Health specialists are here to guide you with personalized care, access to clinical trials and support services for you and your loved ones. Our goal is to help you live as fully as possible while managing the condition. 

Schedule an appointment today and connect with one of our team of experts.