Amyotrophic lateral sclerosis (ALS) – Symptoms and causes

is als genetic

ALS is a shortcut for amyotrophic lateral sclerosis. This is a progressive nervous system disease (it is also known as neurological disease) which destroys nerve cells and causes disability. This disease is also known as Lou Gehrig’s disease which was famous baseball player that was diagnosed with this disease. The amyotrophic lateral sclerosis is a type of motor neuron disease in which nerve cells gradually break down and die. Many doctors do not know the cause for ALS. In some cases, ALS is inherited [1]. This condition often begins with muscle twitching and weakness in a limb or with a slurred speech. ALS can affect the control of muscles which are needed to move, breathe, eat and speak. There is not cure for ALS and eventually it can be fatal.

Symptoms of ALS

Here are early signs and symptoms of ALS [2]:

  • Difficulty holding your head up or keeping good posture
  • Muscle cramps and twitching in your arms, shoulders and tongue
  • Slurred speech or trouble swallowing
  • Hand weakness or clumsiness
  • Weakness in your leg, feet or ankles
  • Tripping and falling
  • Difficulty walking or doing your normal daily activities

This disease often starts in limbs, feet or hands and it spreads to other parts of the body. When the ALS is progressing, then the nerve cells are destroying and the muscles progressively are weakening. This can affect breathing, speaking, swallowing and chewing. This disease is not affecting your bladder or bowel control, your thinking ability or your sense. Also it is possible to stay actively involved with your family and friends.

als prognosis

Causes of ALS

In 5 – 10% of cases this disease is inherited but in other cases the cause for ALS is not known. Doctors are studying several possible causes of this disease, including:

  • The protein mishandling: There are some studies in which are said that the mishandled proteins within the nerve cells can lead to a gradual accumulation of abnormal forms of these proteins in the cells and this will destroy the nerve cells [3].
  • Disorganized immune response: There are some cases when the immune system of some person is attacked by his or her body’s normal cells and this could lead to the death of nerve cells.
  • Chemical imbalance: It is known that those people who suffer from ALS have higher than normal levels of glutamate which is chemical messenger in the brain, around the nerve cells in the spinal fluid. It is known that too much glutamate can be toxic to some nerve cells.
  • Gene mutation: There are some studies in which are said that many genetic mutations which can lead to inherited ALS and this is causing nearly the same symptoms as the noninherited form [4].

Risk factors of ALS

Here are some factors which can increase your risk of ALS:

  • Genetics: There are some studies in which are examined the entire human genome (genomewide association studies) and it was found many similarities in the genetic variations of people who have familial ALS and some people who have noninherited ALS. These genetic variations are increasing the risk of people for getting ALS. [1]
  • Sex: It is known that before the age of 65, slightly more men are developing ALS compared to women. After the age 70 this sex difference disappears.
  • Age: As we are getting older, the risk for ALS is increasing. ALS is most common between the ages of 40 and 60.
  • Heredity: There are some studies in which are said that 5 – 10% of people who suffer from ALS have inherited it (also known as familial ALS). In most people who suffer from familial ALS, their children are having 50 – 50 chance of developing it.

Also environmental factors could trigger ALS, such as

  • Military service: In the recent studies are said that those people who have served in the military are having increased risk of getting ALS. It is not known what about military service can trigger the development of this disease. This can include exposure to certain chemicals or metals, intense exertion, viral infections and traumatic injuries. [5]
  • Environmental toxin exposure: There are some studies in which are said that the exposure to lead or other substances at home or in the workplace can lead to ALS.
  • Smoking: This is one of the biggest triggers for ALS. Women who smoke have more chances of getting ALS, especially after menopause.


[1] NHS. Genetic link for motor neurone disease. 2008.

[2] Genetics Home Reference. Amyotrophic lateral sclerosis. Retrieved from

[3] Science Mission. Mitochondrial localization of a RNA binding protein is required for neuronal toxicity in ALS. 2016. Retrieved from

[4] Conicella AE, Zerze GH, Mittal J, Fawzi NL. ALS Mutations disrupt phase separation mediated by α-helical structure in the TDP-43 low-complexity C-terminal domain. Structure. 2016.

[5] Weisskopf MG, O’Reilly EJ, McCullough ML, et al. Prospective study of military service and mortality from ALS. Neurology. 2005;64(1):32-7.


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