When you have a severe combined immunodeficiency (SCID), your immune system can't fight off even mild infections on its own.
With adenosine deaminase severe combined immunodeficiency (ADA-SCID), your body's defenses stop working because of a problem with your genes.
ADA-SCID is a serious disease that usually shows up early in life. Treatments can help, though, and people who get treatment before an infection happens can live long, healthy lives.
Everyone has ADA genes. If you have ADA deficiency,...