Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, is a progressive neurodegenerative disorder that affects motor neurons in the brain and spinal cord. This condition leads to muscle weakness, paralysis, and eventually respiratory failure. Despite extensive research, there is no cure for ALS, and treatment focuses on managing symptoms and improving a person's quality of life. The Polygenic Risk Score for amyotrophic lateral sclerosis is based on the examination of 9 gene polymorphisms.
Genetic testing for amyotrophic lateral sclerosis is included along with 15 other diseases in the Genetic Screening for Diseases of the Nervous System, Polygenic Risk Score.
Causes and non-genetic risk factors
The cause of amyotrophic lateral sclerosis is not known; however, scientific evidence suggests that both genetics and environment play a role in the degeneration of motor neurons and the development of ALS. In addition to the hereditary factor that accounts for 5-10% of cases, some of the established risk factors for amyotrophic lateral sclerosis include the following:
- Age: The risk of ALS increases with age and is most common between the ages of 40 and mid-60s.
- Gender: Before age 65, amyotrophic lateral sclerosis is slightly more common in men than women. This gender difference disappears after age 70.
- Smoking. Smoking is the only likely environmental risk factor for ALS. The risk appears to be higher for women, particularly after menopause.
- Exposure to environmental toxins. Some evidence suggests that exposure to lead or other substances may be related to amyotrophic lateral sclerosis, although currently, no agent or chemical has been consistently associated.
- Exposure to infectious agents or viruses, physical trauma, diet, strenuous physical activity, and behavioral and occupational factors may impact the development of this disease.
Symptoms
Symptoms of amyotrophic lateral sclerosis vary significantly from person to person. The onset usually begins with muscle weakness that may be so subtle that the symptoms go unnoticed. Over time, it worsens, and symptoms become more obvious weakness or atrophy that makes it impossible to perform routine activities. The most common symptoms include:
- Muscle spasms and cramps, especially in hands and feet.
- Loss of motor control in the hands and arms, muscle stiffness (spasticity), and impaired use of arms and legs.
- Weakness and fatigue.
- Stumbling and falling.
- Uncontrollable periods of laughing or crying.
- Difficulty speaking or projecting the voice.
As the disease progresses, symptoms may include shortness of breath, difficulty breathing and swallowing, and paralysis. Amyotrophic lateral sclerosis sufferers eventually lose the ability to breathe on their own and must rely on a ventilator. Affected individuals also face an increased risk of pneumonia during the later stages of the disease. Fifty percent of affected patients live at least three or more years after diagnosis; 20% live five years or more; and up to 10% will survive more than ten years. The outcome is usually fatal and results from respiratory failure and respiratory insufficiency.
Prevention
Except for hereditary cases, which account for a minority of amyotrophic lateral sclerosis cases, the cause is unknown, so there is no prevention method.
