What is amyotrophic lateral sclerosis?

Although ALS is an incurable and fatal disease, in the last 20 years, new drugs and therapies have been developed that slow its progression and improve patients’ quality of life. Their fight continues.

Amyotrophic lateral sclerosis (ALS) is a degenerative disease that affects motor neurons, responsible for controlling voluntary muscles’ movement. Therefore, it affects the extremities’ muscles initially and even paralysis, subsequently affecting the voice, swallowing, and the ability to breathe. Characteristically, the intellectual capacity remains intact.

Of all the diseases of this type, ALS is the most frequent. Its incidence is approximately three out of every 100,000 people a year, and it affects men more, with an average age of onset of the disease of about 56 years.

A multidisciplinary approach to ALS to improve the patient’s life

It is currently an incurable disease, with a mean survival of around 3-5 years from diagnosis. Only 10% of patients survive more than ten years with ALS. These cases of longer survival tend to be of earlier onset and predominantly muscular and non-bulbar involvement. The end of the disease almost always occurs due to respiratory failure as a consequence of this pathology.

There are two forms: a family of hereditary origin (in 5-10% of cases); and a sporadic, which is the usual form of appearance (in 90% of cases) and occurs randomly and without apparent cause. The SEN also warns that the disease’s diagnosis is usually delayed around 12 months in our country and that 66% of those affected receive alternative diagnoses before.

ALS requires a multidisciplinary approach that encompasses neurologists, physiotherapists, occupational therapists, pulmonologists, nutritionists, and other professionals. It involves a high degree of dependency, complications, and social health costs (around 50,000 euros per year).

Despite its progressive and irreversible nature, scientific advances in recent years have provided multiple medical, orthopedic, and social resources to minimize the consequences of the disease and greatly improve people’s lives with ALS.

Causes of amyotrophic lateral sclerosis

The exact cause of amyotrophic lateral sclerosis (ALS) is unknown. However, it has been attributed to multiple factors such as aging, some viral infection, and heavy metal poisoning (such as mercury, cadmium, lead, and thallium). Only between 5% and 10% of ALS cases appear to be due to hereditary causes.

Among the advances in ALS in recent years, the emphasis has been placed on the chromosomal genetics of hereditary cases, attributing the disease’s cause to multiple mutations (more than 100). In some ALS types, the mutation of the gene encoding the enzyme superoxide dismutase 1 ( SOD1 ) on chromosome 21 has been more specifically identified. This enzyme works abnormally, altering the normal functions of copper and zinc in neurons and causing alterations in the structure of these.

Currently, there are two hypotheses, which have not yet been proven, but which should be highlighted as possible causes of ALS:

  • Deficiency of some type of nerve growth factor.
  • Excess of a neurotransmitter, called glutamate, outside the cells of the nervous system.

In these fields, research in recent years is being emphasized to try to better identify the intimate mechanism that leads to neuronal degeneration that ultimately leads to amyotrophic lateral sclerosis.