Information on Amyotrophic Lateral Sclerosis
What is ALS?
- ALS, or amyotrophic lateral sclerosis, is a chronic progressive
disease characterized by selective degeneration of motor neurons that control voluntary
muscle movement1,2
- Amyotrophic means “without muscle nourishment” and refers to
the loss of signals these neurons normally send to the muscles
- Lateral refers to the location of damage to the spinal cord.
- Sclerosis, or “hardened,” characterizes the nature of the spinal
cord in advanced ALS2
- The incidence of ALS is 2 per 100,000 people,3,4 and it is estimated
that as many as 30,000 Americans have the disease at any given time.3
- Although it can affect anyone, ALS is most common in the 40- to
70-year age range.4
- About 20% of people with ALS live 5 years or more from the time
of diagnosis, and up to 10% will survive more than 10 years.4
- In the US, ALS is also known as Lou Gehrig’s disease, after the
New York Yankee and National Baseball Hall of Fame first baseman, who was one of
the first famous people to become ill with ALS in the early 1940s.2
Forms of ALS
Three classifications of ALS have been described:4
- Sporadic is the most common form in the US, comprising
90% to 95% of cases.
- Familial accounts for 5% to 10% of all cases.
- Guamanian, named for an extremely high incidence of ALS
observed in Guam and the Trust Territories of the US in the 1950s.
Causes of ALS
Although the cause of ALS is not completely understood, recent research suggests
that glutamate, the excitatory amino acid neurotransmitter, may be involved in the
pathophysiology of the disease.1
- Elevated plasma glutamate levels have been observed in patients
with Early stage ALS.5
- Glutamate has neurotoxic properties and can produce lesions resembling
human neurodegenerative disorders.5
- Abnormally enhanced glutamatergic neurotransmission may cause
excitotoxic cell damage and lead to neuronal death.6,7
Clinical Progression of ALS
Muscle weakness is a hallmark initial sign in ALS, occurring in about 60% of patients.
The course of the disease may include the following:4
- Muscle weakness in the hands, arms, and/or legs, or the muscles
of speech, swallowing, and/or breathing.
- Twitching and cramping of muscles, especially in hands and feet.
- Impairment of use of arms and legs.
- “Thick speech” and difficulty in projecting voice.
- Shortness of breath, difficulty in breathing and swallowing in
more advanced stages.
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