X-linked severe combined immunodeficiency 1 (SCID-X1) is a rare inherited disease (almost always in boy babies) in which the body’s cells that fight off infection from certain bacteria, viruses and fungi are lacking or defective. It is called “combined” because both T and B cells are affected. This condition occurs in approximately one of 50,000 newborns.
Typical symptoms of SCID-X1 are early and recurring cases of pneumonia, candidiasis (“thrush”), chronic diarrhea, recurrent eczema rashes, and otitis media. Babies with this abnormality, even though they are protected by their mother’s immunities for a short period after birth, do not grow normally and, if not treated, do not live beyond infancy.
Treatment by transplantation of blood-forming stem cells from the bone marrow of a matched donor has proven successful, especially if administered in the first three months of life.