Lou Gehrig’s Disease (ALS)
WHAT IS ALS?
Amyotrophic lateral sclerosis (a-mi-oh-TROH-fik LAT-ur-ul skluh-ROH-sis), or ALS, is a serious neurological disease that causes muscle weakness, disability and eventually death. ALS is often called Lou Gehrig’s disease, after the famous baseball player who was diagnosed with it in 1939. In the U.S., ALS and motor neuron disease (MND) are sometimes used interchangeably.
ALS often begins with muscle twitching and weakness in an arm or leg, or with slurring of speech. Eventually, ALS affects your ability to control the muscles needed to move, speak, eat and breathe.
Worldwide, ALS occurs in 1 to 3 people per 100,000. In the vast majority of cases — 90 to 95 percent — doctors don’t yet know why ALS occurs. About 5 to 10 percent of ALS cases are inherited. (Mayo Clinic – http://www.mayoclinic.com/health/amyotrophic-lateral-sclerosis/DS00359)
ALS is a disorder that affects the function of nerves and muscles. Based on U.S. population studies, a little over 5,600 people in the U.S. are diagnosed with ALS each year. (That’s 15 new cases a day.) It is estimated that as many as 30,000 Americans have the disease at any given time. According to the ALS CARE Database, 60% of the people with ALS in the Database are men and 93% of patients in the Database are Caucasian. (Information provided by The ALS Association Georgia Chapter – http://webga.alsa.org/site/PageServer/?pagename=GA_1_WhoGets.html)
WHAT IS THE ROLE OF MITOCHONDRIAL IN ALS?
In ALS, evidence is building that actions on or originating in the mitochondria may be an important part of the disease. Changes in the mitochondria can be detected before one can find a physical change such as hind limb weakness in mice.
A role for mitochondria in ALS may explain why SOD1 mutant proteins selectively damage the motor neurons. Some recent studies suggest that mutant SOD1 protein builds up in the mitochondria, unlike normal SOD1 protein which is present throughout the cell but may not be in the mitochondria in healthy cells. This possible shift of mutant SOD1 into the mitochondria may be occurring in motor neurons and not in the liver and kidneys, some evidence suggests.
Mitochondria, as stated earlier, are also involved in the process called apoptosis, a deliberate removal of cells. Some investigators have found that mutant SOD1 attaches to key proteins involved in the cell death process further implicating mitochondria and apoptosis in ALS.
Frank physical damage to the mitochondria is evident in mice with some of the known SOD1 mutations. First, the organelles swell, then they develop empty spaces. Normal mitochondria consist of tightly folded membranes that provide a platform for the metabolic reactions that generate cellular fuel. After the empty spaces appear, the inner membranes of the mitochondria break apart.
The empty spaces appear in mitochondria early in the disease process in the mice. Other researchers have determined that a very early change in mice with mutant SOD1 is a slowing of mitochondrial reactions that provide energy to the cell.
ALS Association–funded researchers are working on all of the intriguing possibilities for a critical role of the mitochondria in ALS. It should be noted that these cellular fueling pumps are also implicated in such neurodegenerative diseases as Parkinson’s and Alzheimer’s.
Information about ALS and Mitochondrial Disease provided by The ALS Association and www.alsa.org.