What is Amyotrophic Lateral Sclerosis, which led to the demise of 'Captain Marvel' actor Kenneth Mitchell at 49?

Canadian actor Kenneth Mitchell, best known for his roles in "Captain Marvel" and "Star Trek: Discovery", has died at the age of 49 due to ASL.

Family breaks the news

In an Instagram post, the actor's family said Mitchell died on Saturday (February 24).

"With heavy hearts we announce the passing of Kenneth Alexander Mitchell, beloved father, husband, brother, uncle, son and dear friend,"the family said in its post.

Mitchell's death comes over five years after he revealed his ALS (Amyotrophic Lateral Sclerosis) diagnosis.

What is ALS?

ALS is a fatal disease that leads to progressive degeneration of nerve cells in the spinal cord and brain. There is no known cure for it.

In an Instagram post in August last year, the actor wrote, "It's been a long 5 years. So much lost, so much gained. Incredibly hard times, mixed with so many more blessings."

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At the heart of it all are friends and family, caregivers and doctors coming to the aid of my family over and over and over again. Giving a plethora of support and love and care and encouragement. There is so much beauty in that. This disease is absolutely horrific.yet despite all the suffering, there is so much to be grateful for, he wrote.

Mitchell is survived by his wife, Susan May Pratt and two children.