How Does Someone Get Lou Gehrig’s Disease?

  • Medical Reviewer: Dany Paul Baby, MD
Medically Reviewed on 6/1/2022

What is Lou Gehrig’s disease?

Lou Gehrig's disease is a progressive and degenerative neurological disease. The cause of Lou Gehrig's disease may be genetics, environmental factors, autoimmunity, or other unknown reasons.
Lou Gehrig's disease is a progressive and degenerative neurological disease. The cause of Lou Gehrig's disease may be genetics, environmental factors, autoimmunity, or other unknown reasons.

Lou Gehrig’s disease is a progressive and degenerative neurological disease. It attacks nerve cells in your spine and brain, and your symptoms steadily worsen as your nerve cells die. For some people, Lou Gehrig’s disease is hereditary or possibly caused by exposure to toxins or other factors. In other cases, there’s no clear cause. 

Lou Gehrig’s disease, or amyotrophic lateral sclerosis (ALS), is a rare neurological disease that affects the motor neurons in your spine and brain. Motor neurons are nerve cells that control your muscle movements. ALS is commonly called Lou Gehrig’s disease after the famous baseball player who died of the disease. 

ALS attacks your nerve cells and the pathways in your spinal cord and brain. The motor neurons waste away and die, leading to worsening muscle weakness and coordination. This causes problems with moving, swallowing, breathing, and speaking, and the symptoms get worse over time. 

Unfortunately, the outlook for ALS is poor. Medication and therapy can help control symptoms and promote independence, but the disease is fatal. 

What causes Lou Gehrig’s disease?

Experts don’t know what causes the exact causes of ALS. Research shows that it could be an inherited genetic disease or linked to some environmental factors.

Another theory says it could be an autoimmune disease where your immune system mistakenly attacks your body. Early animal research suggests that this immune system problem causes inflammation and damage to the nerve cells. But some cases seem to happen without a clear cause, so research is ongoing.  

Genetic disease

About 5% to 10% of all ALS cases are hereditary, which means it’s a genetic disease passed down through families. It’s autosomal dominant, so you only need to inherit one copy of the gene to have the disease. If one of your parents has ALS, you have a 50% chance of inheriting the ALS gene.  

There are more than 25 genes linked to ALS, but some are more common than others. About 20% to 40% of all hereditary cases of ALS have changes in a gene that makes proteins for motor neurons and nerve cells. The cells can’t build, break down, and recycle proteins properly, which causes problems with the cell shape and structure. 

Another 1512% to 20% of cases have changes in the genes for copper-zinc superoxide dismutase enzymes. These enzymes are responsible for protecting your nerve cells from free radicals. 

A free radical is an unstable molecule that your body makes during its normal activities. Because they’re unstable, free radicals cause damage. Normally, copper-zinc superoxide dismutase enzymes help get rid of free radicals before they can damage your cells. In ALS, these enzymes don’t work properly and speed up or promote free radical damage instead of blocking it. 

Recent research also discovered a new gene change linked to childhood ALS. The change affects a gene that converts fats in the body. The conversion process is faulty and creates molecules that damage nerve cells. 

Environmental factors

There might be some links between ALS and lifestyle or environmental factors, though this is still unclear. Exposure to toxins like heavy metals or viruses might increase the risk of ALS. Researchers are also looking at diet, intense physical activity, physical trauma, smoking, and other factors. 

Sporadic factors

For many people, the disease is somewhat of a mystery. In 9 out of every 10 cases, there is no clear cause of the disease. Many patients don’t have family members with the disease, and there don’t seem to be any links to lifestyle, history, or the environment.

In all cases, though, the cells seem to have the same problems: Nerve cell proteins don’t form properly, there are problems with free radicals, and there are problems with other parts of the cells. All of these abnormal activities lead to motor neuron damage, and the cells eventually die. But the reason why this happens isn’t clear. 

Who is most likely to get ALS?

ALS affects people from all races and ethnic groups worldwide, but it’s more common in people who are Caucasian or non-Hispanic. There are some other risk factors too. 

Older people

While ALS can happen in childhood, it commonly starts between the ages of 55 and 75. The age range varies according to the expert, though. Some suggest it can happen earlier, between the ages of 40 and 70 years.


ALS is more likely to affect men than women. About 60% of people with ALS are men, but the rate changes with age, and the difference between men and women evens out after age 60. 

Military veterans and athletes

Some studies suggest that military veterans are 1.5 to 2 times more likely to get ALS. It’s not clear why this is, but it might be linked to exposure to environmental toxins like lead, pesticides, or other chemicals. 

Among the veterans with ALS, those who served in the Gulf War have higher rates. One theory is that they might’ve been exposed to bacteria in the desert sands. Experts are researching possible links.

Athletes are also more likely to get ALS. While the exact causes are unknown and widely debated, both intense exercise and repeated trauma from contact sports are linked to a higher risk of ALS. Spine and head trauma and concussions are linked to ALS too.

How is Lou Gehrig’s disease treated?

There is no cure for ALS, but there are treatments to slow the disease, help your symptoms, and improve your quality of life. 

Disease-modifying treatment

Disease-modifying drugs help reduce the damage to your motor neurons, which slows down the disease. In clinical trials, a drug called riluzole extended survival by three to five months, though it didn’t slow muscle breakdown. Another drug called edaravone also slows down the decline in function and ability. 

Symptom management treatment

Other medications can help with your symptoms, including pain, depression, muscle cramps, insomnia, and stiffness. Physical and occupational therapy can also help you learn new ways to adapt to your changing abilities. 


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Unfortunately, ALS causes a shortened lifespan. The causes are unknown, and there is no cure, but research is ongoing. Treatment can help improve your quality of life and might help slow the disease. 

Medically Reviewed on 6/1/2022

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Muscular Dystrophy Association: "Amyotrophic Lateral Sclerosis (ALS): Causes/Inheritance."

National Institute of Cancer: "Autosomal dominant inheritance."

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