X-Linked Severe Combined Immunodeficiency

X-linked severe combined immunodeficiency (X-SCID) is a severe, genetic condition of the immune system. Signs and symptoms often become apparent in early infancy and include failure to thrive; oral/diaper candidiasis (yeast infection); absent tonsils and lymph nodes; recurrent, persistent infections; rashes; diarrhea; fevers; and pneumonia. X-SCID is caused by mutations in the IL2RG gene and is inherited in an X-linked recessive manner; it only affects males. The condition is typically fatal in the first two years of life unless treated with a bone marrow transplant or gene therapy.