Charcot-Marie-Tooth Disease Type 1A: Experimental Three Part Therapy Shows Potential

According to a story from Charcot-Marie-Tooth News, a recent study suggests that the three components of the investigational therapy PXT3003 work in synergy to improve the condition of patients with Charcot-Marie-Tooth disease type 1A. This is the most widespread variant of the genetic disease. The study tested the drug using an animal model of the illness. PXT3003 contains three that have already been approved for other conditions.

About Charcot-Marie-Tooth Disease

Charcot-Marie-Tooth disease is a hereditary disorder of the peripheral nervous system. It is most characterized by a progressive loss of touch sensation and muscle tissue in several different parts of the body. The cause of this disease is usually linked to a genetic mutation, but the mutation involved varies depending on the variant of Charcot-Marie-Tooth disease. There are multiple types of Charcot-Marie-Tooth disease, with all types aside from type 2 having a demyelination effect. Type 2 causes damage to the neuronal axon instead. Symptoms include foot drop, muscle wasting (typically in the arms, legs, and hands), painful muscle spasms, loss of sensation in the limbs, scoliosis, trouble speaking, chewing, swallowing, and tremors. Treatment typically includes therapy and surgery in order to maintain function. There is no cure. The disease can occur early in life or as late as the 30’s and 40’s. To learn more about Charcot-Marie-Tooth disease, click here.

The Type 1A Variant

The type 1A variant of the illness is linked to a mutation the causes an extra copy of the PMP22 gene to appear. This gene produces a protein called PMP22 which is produced too much when the extra copy is present. The extra PMP22 can cause problems with the formation of the myelin sheath, a fatty, insulating layer that surrounds and protects nerve cells and is critical for their normal function. 

About The Study

PXT3003 consists of three components: sorbitol, which is normally used to treat constipation; naltrexone, typically used to treat addiction; and baclofen, which is a muscle relaxant. While the combination has shown potential in trials, this study is helping scientists understand more about how the drug works. The researchers treated cells from the animal model with either one, two, or all three of the components. Only when they were all combined did myelination improve (by 24.6 percent).

Similar findings appeared when rats with the disease were treated with the various combinations. Only all three together triggered improvements. The rats saw improvements in movement and motor function that were linked to increased size of neuromuscular junctions and density that was reduced to within the ranges found in unaffected rats. In addition, a smaller number of muscle cells were atrophied in the rats that were treated with all three.

Learn more about this study here.

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