WAS gene

The WAS gene provides instructions for making the WASP protein, which is essential for blood cell function, immune system response, and blood clotting.

Normal Function

The WAS gene provides instructions for making a protein called WASP. This protein is found in all blood cells and is involved in relaying signals from the surface of blood cells to the actin cytoskeleton, a network of fibers that forms the cell's structural framework. WASP signaling triggers the cell to move and attach to other cells and tissues (adhesion). In white blood cells, this signaling allows the actin cytoskeleton to establish the interaction between cells and foreign invaders, known as the immune synapse.

Health Conditions Related to Genetic Changes

Wiskott-Aldrich syndrome

More than 350 mutations in the WAS gene have been found to cause Wiskott-Aldrich syndrome, a condition characterized by abnormal immune system function (immune deficiency) and a reduced ability to form blood clots, leading to prolonged bleeding episodes. Most of these mutations lead to the production of an abnormally short, nonfunctional version of WASP or prevent its production entirely. This results in several issues:

• White blood cell impairment: Cells lack the ability to respond to their environment and form immune synapses, making them less effective at responding to foreign invaders.
• Platelet dysfunction: Cells that aid in blood clot formation have impaired development, reduced size, and early cell death, leading to bleeding problems.

X-linked thrombocytopenia

More than 60 mutations in the WAS gene have been found to cause X-linked thrombocytopenia, a blood disorder characterized by a decrease in the amount and size of platelets, leading to prolonged bleeding. Immune problems, such as increased susceptibility to infections, may also occur. These mutations typically change single protein building blocks (amino acids) in WASP, resulting in an altered protein that cannot efficiently relay signals from the cell membrane to the actin cytoskeleton.

Because Wiskott-Aldrich syndrome and X-linked thrombocytopenia share overlapping features and the same genetic cause, they—along with severe congenital neutropenia—are sometimes collectively referred to as WAS-related disorders.

Severe congenital neutropenia

The WAS gene is also associated with severe congenital neutropenia.

Genomic Location

The WAS gene is found on the X chromosome.