PRX

The PRX gene provides instructions for making a protein called periaxin. Periaxin is required for the maintenance of myelin, the protective substance that covers nerves and promotes the efficient transmission of nerve impulses. The exact function of periaxin is unclear, but research suggests that it helps to stabilize the myelin.

The PRX gene produces two forms of periaxin, called long (L) and short (S) because they differ in size. Research studies show that the short form (S-periaxin) is distributed throughout the cytoplasm, the fluid inside cells. The long form (L-periaxin) is concentrated initially in the cell nucleus, then relocates to the cell membrane during the formation of myelin. L- and S-periaxin probably have slightly different functions, based on their different cell locations.

Charcot-Marie-Tooth disease - caused by mutations in the PRX gene

Researchers have identified several PRX mutations that cause a form of Charcot-Marie-Tooth disease known as type 4F (sometimes called Dejerine-Sottas syndrome). One mutation affects both L- and S-periaxin, while the other mutations affect only L-periaxin. An abnormally short protein is produced as the result of PRX mutations. The shortened protein cannot perform its normal function, maintaining the myelin structure. Disrupted myelin structure can lead to the loss of myelin (demyelination), which can impair the transmission of nerve impulses and cause the signs and symptoms of type 4F Charcot-Marie-Tooth disease.