What is ALS? Oak Ridge Boys member Joe Bonsall died from complications from this rare disease. Here's what to know

Vocalist Joe Bonsall died on July 9 due to complications from ALS. The singer was one of approximately 31,000 people in the United States who are affected by this rare neurological disease.

Bonsall, 76, was the tenor vocalist for the Oak Ridge Boys for decades before retiring six months ago due to amyotrophic lateral sclerosis, better known as ALS. The singer spent five years performing with the group while battling the fatal disease that weakens the muscles in people who suffer from it.

"It has been a great 50 years and I am thankful to all the Oak Ridge Boys, band, crew and staff for the constant love and support shown to me through it all. I will never forget, and for those of you who have been constantly holding me up in prayer," stated Bonsall in January to The Tennessean.

Here's more on the disease that Bonsall had.

What is ALS?

ALS is a degenerative nervous system disease that affects nerve cells in the brain and spinal cord. The disease leads to loss of muscle control in the body, people affected by ALS could experience muscle twitching and weakness in an arm or leg, trouble swallowing or slurred speech as the disease progresses, according to the Mayo Clinic.

The disease eventually progresses to the point that people can become wheelchair-bound and lose control over the muscles that help them move, talk, eat and even breathe.

People diagnosed with ALS are usually between the ages of 40 and 70, with an average age of 55 at the time of diagnosis, according to the ALS Association. But people younger than that can be affected by ALS.

What causes ALS? Is there a cure?

There is no known cause of ALS and there is no cure, according to the ALS Association.

Does ALS go by a different name?

It is also known as Lou Gehrig's disease after the famous baseball player who was diagnosed with it. He was diagnosed with ALS in 1939, ending his career with the New York Yankees.

The disease was first discovered by French neurologist Jean-Martin Charcot in 1869, but it was Gehrig's diagnosis and subsequent death in 1941 at the age of 37 that led to the disease becoming more widely known and receiving the name Lou Gehrig's disease.

What are the symptoms of ALS?

ALS can manifest in people differently, but it usually starts with weakness that spreads or gets worse over time, according to the Mayo Clinic. Here are some of the symptoms of this fatal disease.

• Trouble walking or doing usual daily activities
• Tripping and falling
• Weakness in the legs, feet or ankles
• Hand weakness or clumsiness
• Slurred speech or trouble swallowing
• Weakness associated with muscle cramps and twitching in the arms, shoulders and tongue
• Untimely crying, laughing or yawning
• Thinking or behavioral changes

When is Joe Bonsall's funeral?

At Bonsall's request, there will be no funeral. Instead of flowers, donations may be made to The ALS Association or the Vanderbilt Medical Center ALS and Neuroscience Research Center.