RAB7A

Certain substances, such as proteins and fats, are moved around within cells by small saclike structures called transport vesicles. The RAB7A gene provides instructions for making a protein that helps regulate the traffic patterns of these vesicles. This protein is part of the RAB protein family. Each member of the RAB family appears to play a role in moving substances to specific compartments within the cell. The RAB7A protein regulates transport from the cell surface to cell compartments called lysosomes. Lysosomes are filled with enzymes that break down toxic substances, digest bacteria that invade the cell, and recycle worn-out cell components. The RAB7A protein is essential for the maintenance of functional lysosomes.

Charcot-Marie-Tooth disease - caused by mutations in the RAB7A gene

Researchers have identified at least four RAB7A mutations that cause a form of Charcot-Marie-Tooth disease known as type 2B. These mutations replace one of the building blocks (amino acids) used to make the RAB7A protein with an incorrect amino acid. These changes probably alter the structure of the RAB7A protein and impair its function. Research studies indicate that lysosomes break up and disperse if the RAB7A protein is malfunctioning. Without lysosomes, cells cannot break down toxic substances or recycle cell components. It remains unclear, however, how the altered RAB7A protein leads to the signs and symptoms of type 2B Charcot-Marie-Tooth disease.