Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS), although the rarest of the neurodegenerative diseases, is in many ways the most devastating.

It is characterized by relentless muscle wasting and weakness involving limb and bulbar musculature. Death prevails usually from respiratory failure, in an average of 3 ½ years following onset of symptoms. There are approximately 5000 cases of ALS in Canada, with the addition of about 500 new cases each year. Onset most commonly occurs between 50 and 65 years of age, but younger onset cases are becoming more frequent. The incidence of ALS, as is the case for other neurodegenerative diseases, is increasing as Canada’s population ages. It is predicted that by the year 2030, one in four families will have a member with Alzheimer’s, Parkinson’s, or ALS.

There are different forms of ALS. The most common one is called Sporadic ALS. Less common is Familial ALS, an inherited type that represents approximately 5–10 % of ALS cases in Canada. The cause of ALS is still not fully known. While it was once thought that ALS was caused by a single factor, it is now accepted that it likely has multiple interacting causes, many of which are not understood, which lead to the destruction of motor neurons. And although it is accepted that genetic factors play a role in ALS, it is not fully understood whether a variety of environmental toxins, so far unidentified, may also play a role. What is understood, though, is that the disease is propagated by a complex self-sustaining, largely genetically-dependent, age-related series of events that include oxidative stress, excitotoxicity, accumulation of intracellular aggregates, disordered immune responsiveness and inflammation, mitochondrial dysfunction, and inappropriate apoptosis (programmed cell death).