Severe combined immunodeficiency disease (SCID) is a rare immune system disorder that affects infants. Also known as the "bubble boy disease," SCID is caused by genetic mutations that prevent the body's ability to fight off infections. There are a few synonyms for SCID, including "bubble boy syndrome," "T-B+NK-SCID," and "genetic immunodeficiency disease." Symptoms of SCID include recurrent infections, chronic diarrhea, and failure to thrive. Treatment for SCID typically involves bone marrow or stem cell transplantation, but early detection is crucial to prevent serious infections and improve quality of life. While SCID is a serious condition, advances in medical research have enabled children with this disorder to lead normal, healthy lives with proper care and treatment.