DNM2

The DNM2 gene provides instructions for making a protein called dynamin 2. Dynamin 2 is present in cells throughout the body and plays a role in several cell activities. One such activity is a process called endocytosis, by which cells transport materials from outside to inside the cell. Through this process, the cell membrane folds around a substance outside the cell and forms a saclike vesicle. The vesicle is drawn into the cell and is pinched off from the cell membrane. Dynamin 2 is thought to play a key role in altering the cell membrane to form these vesicles. This protein probably also participates in moving vesicles within the cell. Additionally, dynamin 2 associates with tubelike structures, called microtubules, which are part of the cell's structural framework (cytoskeleton). The cytoskeleton helps to define cell shape and organize cell contents, and aids in cell movement. Microtubules are also essential for cell division. In a related role, dynamin 2 appears to be important for the structure of a cell component called the centrosome, which is the organizing center for microtubules.

Charcot-Marie-Tooth disease - caused by mutations in the DNM2 gene

Researchers have identified a few DNM2 mutations that cause a form of Charcot-Marie-Tooth disease known as dominant intermediate B. These mutations alter the number or types of protein building blocks (amino acids) used to make dynamin 2. One mutation replaces the amino acid lysine with the amino acid glutamic acid at protein position 558 (written as Lys558Glu). As a result of other mutations, dynamin 2 is missing one or more amino acids.

DNM2 mutations alter the structure of dynamin 2, which affects the activity of this protein. Studies have shown that certain mutations disrupt microtubules in the cytoskeleton and disturb cellular organization. It is unclear, however, how DNM2 mutations cause the signs and symptoms of dominant intermediate B Charcot-Marie-Tooth disease.

other disorders - caused by mutations in the DNM2 gene

DNM2 mutations also cause a disorder called autosomal dominant centronuclear myopathy, which is characterized by muscle weakness and wasting. People with this disorder often have eye abnormalities such as droopy eyelids (ptosis) or limited eye movements. The DNM2 mutations change one of the protein building blocks (amino acids) used to make dynamin 2, which alters the protein's structure. Research indicates that these mutations impair the protein's interactions with other components of the centrosome. It is unclear, however, how DNM2 mutations cause the signs and symptoms of centronuclear myopathy.