What is ALS?
Amyotrophic lateral sclerosis (ALS) is one of the most severe neurodegenerative diseases in humans, first described in 1874 by the French neurologist Jean-Martin Charcot. Other names for the disease are amyotrophic lateral sclerosis, myatrophic lateral sclerosis, Lou Gehrig’s syndrome (after the baseball player Lou Gehrig, who was affected by the disease). In English, the disease is called amyotrophic lateral sclerosis (ALS) or motor neurone disease (MND).
In ALS, there is progressive and irreversible damage to the so-called motor neurons, also known as motoneurons, i.e. those nerve cells that are responsible for muscle movements. Both the first motoneuron, which is located in the cerebral cortex, and the second motoneuron in the spinal cord, whose processes lead to the skeletal muscles, are affected. If these neurons are damaged, the muscles are no longer supplied with sufficient nerve stimuli.
The first motoneuron is also called the upper motor neuron because it is superior to the second, lower motor neuron. If this fails, a so-called spastic paresis (involuntary muscle twitching, cramping, paralysis) occurs. If the lower second motor neuron is damaged, the muscles go limp. Consequences: Muscle atrophy, muscle weakness in the arms, legs and also the respiratory muscles. The first symptoms of the disease appear in different places depending on the patient. Sometimes muscle atrophy and weakness first appear in the hand and forearm muscles on one side of the body before spreading to the other side and to the legs. Sometimes the symptoms of damage to both motoneurons occur simultaneously, for example paralysis in the arms as a sign of damage to the second motoneuron with simultaneous increased tone of the leg muscles as a sign of damage to the first motoneuron, In a small proportion of sufferers, the symptoms first appear when speaking, chewing and swallowing, this course is called bulbar.
ALS occurs worldwide and is one of the rare diseases. Every year, approximately 1 to 3 out of 100,000 people are newly diagnosed with ALS (incidence). The number of people with the disease at any given time is 3 to 8 per 100,000 people (prevalence). Most disease occurs between the ages of 50 and 70, with the median age of onset being 56 to 58 years. Rarely, ALS affects younger patients between 25 and 35 years of age.
In Germany alone, approximately 8,000 patients are affected by this disease, and about 2,000 die from it each year. Despite intensive research, the causes of ALS are still not fully understood and the therapeutic options are limited to the treatment of the symptoms. There is no cure, and the average survival time is 4-5 years. Nevertheless, this disease is insufficiently perceived by the general public in this country. Therefore, it is imperative, on the one hand, to sharpen society’s view of this disease and, on the other hand, to develop faster diagnostic procedures, for example by means of biomarkers, as well as novel therapeutic strategies.