Amyotrophic Lateral Sclerosis (ALS) is a diagnose that change forever the life of everyone: patient, family, and friends. The name refers to the scarring (sclerosis) that involves the lateral area of spinal cord leading to muscular atrophy (amyotrophic).
It is a neurologic disease in which happen the degeneration of motor neuron, in other words, the neuron which is responsible to send orders from the brain to muscular voluntary contraction is damaged. There are two types of motor neuron: upper motor neuron or first motor neuron, which origin is in the brain and go down through the spinal cord; and the lower motor neuron or second motor neuron, which origin is in the spinal cord or brainstem and go to the voluntary muscle. In ALS it is seem the progressive loss of upper and lower motor neuron.
Adults with all ages can have ALS; however, it is most frequent between the ages 65-74 years old. It is also slightly common in men than women (1.8 man: 1 woman). The ALS incidence is uniform around the word, except for some area in Japan and Guam Island, where the ALS incidence is higher. Every year, there are 3 new cases in a group of 100,000 people; and about 6 people have ALS in a group of 100,000. Using this data, is possible to say that we have around 12,000 people with ALS in Brazil.
The most common form of ALS is called Sporadic ALS. In that type of ALS the cause is unknown. Some hypotheses to explain include virus infection, toxin exposure, hormone alteration and immune system activation. However, none of these hypotheses was confirm by epidemiological study. It is likely that there is not just one cause, but different facts that trigger the disease in predisposed person.
Only 10% of the ALS cases have genetic origin. Some ALS familiar gens were already identified, but still have others to be discovered. When more than one person in the family is diagnosis with ALS, is possible to do the genetic test in order to try to find the mutation and test whether other member of the family have the same gene. However, is important to remember that only the presence of the gene does not mean that the person will develop ALS, there are other facts involved in this disease.