What is ALS and what are the symptoms and causes?

Progressive neurodegenerative disease suffered by Sandra Bullock’s partner Bryan Randall affects nerve cells in the brain and spinal cord

Kenneth Mitchell, the Canadian actor known for roles in Captain Marvel and Star Trek: Discovery, has died from complications of ALS.

Mitchell, who was 49-years-old, died on Saturday, according to a statement released by his verified Instagram account.

ALS affects nerve cells in the brain and spinal cord, its name coming from the Greek and referring to a wasting away of the muscles responsible for controlling voluntary movement caused by a lack of nourishment, the fault of a genetic mutation.

As the ALS Association explains: “Motor neurons reach from the brain to the spinal cord and from the spinal cord to the muscles throughout the body. The progressive degeneration of the motor neurons in ALS eventually leads to their demise.

“When the motor neurons die, the ability of the brain to initiate and control muscle movement is lost. When voluntary muscle action is progressively affected, people may lose the ability to speak, eat, move and breathe.

“The motor nerves affected when you have ALS are the motor neurons that provide voluntary movements and muscle control. Examples of voluntary movements are making the effort to reach for a smartphone or step off a curb. These actions are controlled by the muscles in the arms and legs.”

Early symptoms of the disease, according to the US National Institute of Neurological Disorders and Strokes (NINDS), include: muscle twitches in the arm, leg, shoulder or tongue; cramps; tight or stiff muscles; muscle weakness; slurred or nasal speech; and difficulty chewing and swallowing.

Kenneth Mitchell in 2017 (Rob Latour/Shutterstock)

“The first sign of ALS usually appears in the hand or arm and can show as difficulty with simple tasks such as buttoning a shirt, writing, or turning a key in a lock,” the NINDS explains.

“In other cases, symptoms initially affect one leg. People experience awkwardness when walking or running, or they may trip or stumble more often.”

There is currently no cure for ALS but the US Food and Drug Administration has approved a number of drugs to ease the discomfort of sufferers such as Riluzole and Radicava.

It was first discovered by French neurologist Jean-Martin Charcot in 1869 and is also commonly known as Lou Gehrig’s disease in memory of the celebrated New York Yankees baseball star (1903-41) who also suffered from it.

Baseball star Lou Gehrig at the bat in 1930 (Hulton Archive/Getty)

While ALS affects all demographics, it is most common among people aged between 55 and 75 and, according to some studies, disproportionately affects former members of the armed forces, perhaps because of exposure to harmful toxins during their service careers although this has not been definitively substantiated.

The ALS Association reports that, in 90 per cent of cases of ALS, there is no family history of the genetic mutation that causes the disease and, in the 5-10 per cent of cases in which there is, only a 50 per cent possibility exists of its being passed on.

For more information, please visit the websites of the ALS Association or the National Institute of Neurological Disorders and Strokes.