A recent article in the neuroscience section of the Medical Express reports the results of a study conducted by researchers in the Charcot-Marie-Tooth/Hereditary Neuropathy Center at internationally acclaimed Cedars-Sinai.
The Center at Cedars-Sinai is composed of specialists from the departments of medical genetics, pediatrics, orthopedics, and neurology and provides diagnosis and treatment for Charcot-Marie-Tooth (CMT) disease.
Parkinson’s, Alzheimer’s, and Charcot-Marie-Tooth disorders have something in common: the deterioration of the nervous system. Together these three diseases and other related disorders affect millions of people in the United States and around the world.
Considerable research, including extensive research on the mitochondrial proteins, have been conducted on these diseases. Yet, to date, the cause of CMT and the other diseases remains unknown.
About CMT
CMT was identified in 1886 and named after the three doctors who discovered the disease, Dr. Jean-Martin Charcot, Dr. Pierre Marie, and Dr. Howard Henry Tooth.
It is a genetic disorder (inherited) with symptoms affecting the lower extremities such as abnormalities in toes, feet arches, balance, and various levels of pain. Approximately 150,000 people in the United States are known to have the disease.
CMT progression includes loss of muscle tissue and may advance to other areas such as the hands and affect overall touch sensation. Although the disease is not life-threatening, it does have a severe impact on the quality of a patient’s life.
There are many types of CMT with CMT1 being the most common. Additional symptoms may occur in CMT type 2A such as wearing away of the optic nerve, damage to the spinal cord, and damage to tissues in the brain.
Current Treatment for CMT
Therapy for CMT depends upon its severity. Treatment may include occupational and physical therapy. In order to stabilize the lower extremities but still allow motion, therapists use specialized braces. Surgery that does not fuse bones may also be required to correct foot deformities.
About the Multi-institutional Study
The results of the study provide a gateway to treatments for CMT and give new insight to neurodegenerative disorders such as Alzheimer’s.
The word neurodegeneration is a combination of neuro, meaning nerve cells and degeneration which refers to potential damage of the nerve cells. The disease occurs when various factors begin to affect the neurons in the brain.
According to an article in the Journal of Clinical Investigation, a more precise definition would describe a disorder that “. . . affects specific subsets of neurons in specific functional anatomic systems (relating to the anatomy).” The cause is unknown but the Journal reports that they “progress in a relentless manner.”
The main focus of the study were two proteins (MFN1 and MFN2). These proteins are located inside cells on the outer membranes of structures called mitochondria. Thousands of energy producing mitochondria exist in each cell.
Prior studies revealed that when the protein MFN2 is mutated the mitochondria will malfunction in CMT type 2A.
About the New Research
The Journal article reported that during an experiment on laboratory mice, researchers increased the levels of MFN1 which compensated for the effects of the mutated MFN2. The result was that the symptoms and neurodegeneration of CMT type 2A were reduced.
The researchers were able to study CMT type 2A by putting a human gene with the MFN2 mutation into the genome of the lab mice. The mice that received the mutated MFN2 did develop CMT type 2A symptoms. But when MFN1 or normal MFN2 were increased in these mice, the symptoms almost completely disappeared.
Although the mutated MFN1 occurs in every cell throughout the body, CMT type 2A mostly occurs in the nervous system. The researchers point out that the reason for this lies in the fact that levels of MFN1 are much lower in brain cells. They explain that increasing levels of MFN1 will improve the function of mitochondria.
These research findings are especially valuable because this new approach to reducing symptoms of CMT type 2A can extend to similar diseases involving dysfunction of the mitochondria.
In addition to CMT type 2A, the specific diseases that would be targets of the new research are Parkinson’s, Alzheimer’s and ALS. These diseases affect approximately seven million people in the United States.
