Combined immunodeficiency due to CARMIL2 deficiency is a rare, inherited disorder that affects the immune system. It is caused by mutations in the CARMIL2 gene, which is responsible for producing a protein called CARMIL2. People with this disorder have a weakened immune system, which makes them more susceptible to infections. Symptoms may include recurrent infections, failure to thrive, and skin rashes. Treatment typically involves antibiotics, immunoglobulin therapy, and bone marrow transplantation.