Compared to diseases such as cancer or heart disease, Amyotrophic Lateral Sclerosis (ALS), affects very few people, only about 20,000-30,000 people in the United States (National Institute of Neurological Disorders and Stroke, 2013) and 2,500-3,000 in Canada (ALS Canada, 2013). It is responsible for about 2 deaths of every 100,000 people. Yet, ALS, often referred to as Lou Gehrig's disease, is relatively well known across the population. Why is this?
One of the reasons certainly has to do with the name Lou Gehrig, a famous baseball superstar who had to suddenly retire in 1939 due to ALS and then passed away shortly after. But, another reason ALS is so well known is undoubtedly due to it being an especially devastating disease with horrific effects and no known cure despite years of research.
While recorded reports on symptoms that appear to be Amyotrophic Lateral Sclerosis date from as far back as 1824, the first description in scientific literature was by a French neurologist named Jean-Marie Charcot. Charcot published his findings on the characteristics of ALS in 1869 (Yale, 2013). But it wasn't until Lou Gehrig's major announcement in 1939 that there was a widespread public recognition of the disease, especially in the Western world.
ALS is one of the most common neuromuscular diseases around the world, and people of all races and ethnic backgrounds are affected. On average about one to three out of every 100,000 people develop ALS each year (Kinsley & Siddique, 2013). ALS is usually diagnosed in people between 40 and 60 years of age, but younger and older people can also develop the disease. Men are affected slightly more often than women (National Institute of Neurological Disorders and Stroke, June 2013)
Despite years of research, the precise cause of ALS is still not known. In 1993 a first important step toward determining the cause came when scientists discovered that mutations in the gene that produces the superoxide dismutase (SODl) enzyme were associated with some cases (Rosen et al, 1993; NINOS, 2003). As a result, it was determined that ALS can be a result of hereditary factors, particularly in familial ALS (FALS), which is about 5 percent of all cases (ALS Association, 2014). A defect on chromosome 21,which codes for SOD, has been linked with approximately 20% of familial cases of ALS, or about 2% of all ALS cases (Conwit, 2006). With the rapid advancements in molecular biology scientists are discovering additional genetic mutations linked to ALS and it is becoming increasingly clear that many cellular defects can be responsible for the motor neuron degeneration of ALS (NINOS, 2003).
While about 30% of familial ALS cases have an identified genetic cause, this still leaves a large question as to the cause in the overwhelming 95% of cases where there is no hereditary link for ALS (Talbot 2011). This type of ALS, known as sporadic, may also have some genetic causes, but this is still unclear (Valdesa &...