Question: What happens to the motor neurons when a person has this disease ( ALS and motor neuron disease ) and did Stephen Hawking have it?

Gaby Clarke answered on 30 Jun 2020:

Hi Polina!
When someone has ALS, the motor neurons that connect their brain to their muscles start to die. This can happen due to many different reasons and sometimes depends on the specific ALS-causing genetic mutation that the patient with ALS has. For example, I am interested in the toxic aggregation of proteins within the motor neuron. I am also interested in hyperactivity of the motor neuron (where the neuron fires its electrical signals too often) that can lead to cell death (known as excitotoxicity). Regardless of how, when the motor neurons die, they lose their connections (known as neuromuscular junctions) to the muscle, resulting in muscle paralysis. This is why advanced ALS patients are in wheelchairs and cannot move, speak or eat for example.

Stephen Hawking did have ALS, and many scientists are still baffled as to how he lived so long with it! Most people with ALS get diagnosed by a doctor when they are between the ages of 45 and 65, and then they only live for another 5 years or so. Stephen Hawking was diagnosed with ALS when he was only 21 (known as juvenile-onset), then lived for another 55 years! It seems that the death of his neurons happened very slowly over time so he lived for a lot longer than expected. But we don’t really know why!