Amyotrophic Lateral Sclerosis (ALS)

What is Amyotrophic Lateral Sclerosis (ALS)?

Amyotrophic Lateral Sclerosis is a neuro- muscular disease that causes degeneration of voluntary muscles and nerves. Stephen Hawking is a famous personality affected by ALS.

Other names - Maladie de Charcot, Lou Gehrig's disease, Motor Neurone Disease (MND)

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive and fatal disease that is caused by the degeneration of motor neurons that control voluntary muscular movements of the body.

It is also called Lou Gehrig's disease after the famed American baseballer by the same name, who died of ALS in 1941, aged 37. Stephen Hawking, the world renowned physicist, is among those afflicted, currently alive.

ALS is classified under 'motor neuron disorders' and is characterized by the gradual degeneration of motor neurons which are nerve cells localized in the brain, brainstem, and spinal cord which control communication between the nervous system and the voluntary muscles all over the body.

Upper motor neurons (brain)
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Lower motor neurons (spinal cord)
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Voluntary muscles

The disorder begins when the upper and lower motor neurons degenerate and stop sending signals to the muscles bringing about weakening, twitching (fasciculation) and their eventual atrophy. Initially the disease may manifest as difficulty in walking or running, writing or speech. The patient may ultimately loose control over all voluntary movements and there comes a stage when the brain no longer controls voluntary movements of the body and the patient becomes weak and is unable to walk or move his arms or legs.

Breathing too becomes difficult as the muscles of the chest and the diaphragm are damaged. Although a ventilator may help for a while, the afflicted persons very often die from respiratory failure within 3-5 years of disease onset.

Generally, the intelligence of the patient is not impaired. However certain changes in cognitive function is brought about such as memory loss, problems with making decisions and depression. However, the person's ability to see, smell, hear, taste or touch is not affected.

ALS is one of the common neuromuscular diseases which mostly affects men, more than women, of all races and ethnic background. Majority of the disease ( almost 90%) is sporadic and only in 10% of cases are familial (inherited). It is generally seen in people aged over 50 years.

The actual causes of ALS are not very clear. Familial predisposition has been implicated, but in the vast majority of affected people it occurs de novo. In 90-95% of ALS cases the disease is not familial, but occurs sporadically.

5-10% of all ALS cases are genetically determined. One-fifth of these cases occur due to a mutation in the gene SOD1 that codes for the enzyme superoxidase dismutase 1. It is obvious that other genes are involved and are waiting to be discovered.

ALS cannot be completely cured but medications are available that can control the symptoms and prolong life. Some people can live for as long as even ten years with proper treatment.