GDAP1

The GDAP1 gene provides instructions for making a protein called ganglioside-induced differentiation-associated protein 1. This protein is found in the outer membrane of mitochondria, the energy-producing centers within cells. Mitochondria are dynamic structures that change shape through processes called fission (splitting into smaller pieces) and fusion (combining pieces). Changes in shape are thought to be critical for mitochondria to work properly. Although the function of the GDAP1 protein is not well understood, it appears to play a role in controlling the shape of mitochondria by promoting fission.

Charcot-Marie-Tooth disease - caused by mutations in the GDAP1 gene

Researchers have identified more than 50 mutations in the GDAP1 gene that can cause Charcot-Marie-Tooth disease, a disorder that results in muscle weakness, wasting (atrophy) of muscles, and loss of sensation in the feet, legs, and hands. Some of these mutations create a premature stop signal in the instructions for making the GDAP1 protein. As a result, cells produce an abnormally short protein that is unlikely to be inserted correctly into the outer membrane of mitochondria. Other mutations change single building blocks (amino acids) used to make the GDAP1 protein, which may alter its shape or function.

It is unclear how GDAP1 gene mutations lead to the characteristic features of Charcot-Marie-Tooth disease. These mutations probably impair the mitochondria's ability to change shape, but how this impairment affects the peripheral nerves is not well understood.