Amyotrophic lateral sclerosis (ALS), or Lou Gehrig’s disease, is a neurodegenerative disease that affects nerve cells in the brain as well as spinal cord. The word “amyotrophic” comes from Greek and can be directly translated as “no muscle nourishment.” The word “lateral” is used to identify the location of the nerve cells in the spinal cord responsible for signaling and controlling the muscles. As the disease progresses, the areas degenerate, which leads to hardening or scarring (“sclerosis”).
Individuals who develop ALS are usually 40-70 years old, with 55 being the average age at the time of diagnosis. In some instances, the disease can occur in individuals who are 20-30 years old. ALS is 20% more common in men, but as people age, their risk of developing ALS increases, and the percentage of developing the disease based on gender becomes more equal.
Scientists investigate the risk factors possibly associated with the disease. However, not enough studies have been completed and published on the environmental or genetic factors that contribute to developing ALS. Among the possible causes of the disorder being researched are oxidative stress, mitochondrial dysfunction, abnormalities in the immune system, glutamate toxicity, and toxic exposures.
Half of individuals who develop ALS live at least three or more years after diagnosis, while 20% live five or more years, and 10% live more than ten years.
ALS is the type of disease that progresses gradually. Different individuals may have different first symptoms of the disorder. Some people may experience a change in voice when speaking, while others can find it difficult to grasp a pen or lift a cup of coffee.
The rate of progression also varies from one person to another. While on average people live 3-5 years after the diagnosis, some people can live more than ten years. They may experience different symptoms and different disease progression, but all ALS patients will have progressive muscle weakness and paralysis.
Progressive muscle weakness is the common first symptom of ALS. Other symptoms that occur early can include dropping things, tripping, slurred speech, abnormal fatigue in legs and arms, uncontrollable laughter, or muscle cramps. After the disease affects breathing muscles, patients require ventilatory support for breathing assistance. Patients do not lose their sense of sight, hearing, touch, smell or taste, because ALS affects only motor neurons
Currently there are two main classifications of ALS, including sporadic and familial. Scientists have also identified two rare cases of ALS, such as Guamanian and ALS-parkinsonism-dementia complex.
Sporadic ALS is the most common type of ALS, which accounts for 90-95% cases. It occurs without family history, but sometimes genetic variations affect the likelihood of developing the disease without causing it. The first symptoms can appear in the patients in their late 50s or early 60s.
Familial ALS accounts for the remaining 5-10% cases where the disease arises in families with history of ALS. Scientists have identified the genes associated with the disease and their location in a chromosome. Familial ALS can occur more than once in a family, with the first signs showing in the late 40s or early 50s.
Guamanian ALS was discovered in the 1950s in Guam and Trust Territories of the Pacific, as the incidence of the disease was extremely high.
ALS-parkinsonism-dementia complex is a rare form of ALS and is often familial. Patients with this form of disease demonstrate symptoms of ALS as well as movement abnormalities, including tremors, stiffness, and unusually slow movements, which are known as symptoms of parkinsonism.
If more than one person in the individual’s family was diagnosed with ALS or a relative had ALS at a younger age (45), they may decide to undergo genetic testing. This type of test is most effective in an individual diagnosed with ALS. The test can identify genetic mutation that caused the disease and investigate if the family members inherited the mutation. Consulting with genetic counselor will help the patients decide whether they should participate in genetic testing.
Diagnosis of ALS requires a series of diagnostic tests and clinical examinations to eliminate the possibilities of other diseases with similar symptoms. The procedures include electro diagnostic tests, blood and urine samples, spinal tap, X-rays and MRI, nerve or muscle biopsy, neurological examinations, and myelogram of cervical spine. Since there are treatable conditions with the same symptoms as ALS, it is important to seek advice from ALS specialist.
The ALS Ice Bucket Challenge started in the summer of 2014 and became the world’s largest global social media phenomenon. More than 17 million people uploaded their challenge videos to Facebook; these videos were watched by 440 million people a total of 10 billion times. It is now an annual event to raise awareness and funds to find treatments and a cure for amyotrophic lateral sclerosis (ALS).