Combined immunodeficiency due to DOCK8 deficiency is a rare, inherited disorder that affects the immune system. It is caused by mutations in the DOCK8 gene, which is responsible for producing a protein that helps regulate the activity of certain white blood cells. People with this disorder have a weakened immune system, which makes them more susceptible to infections. Symptoms may include recurrent infections, skin rashes, and enlarged lymph nodes. Treatment typically involves antibiotics, immunoglobulin therapy, and bone marrow transplantation.