a rare disorder that usually manifests itself within the first three months of life by severe bacterial, fungal, and viral infection and failure to thrive. It is due to reduced numbers of T- and B-lymphocyte - white blood cells necessary for fighting infection. Some cases are caused by adenosine deaminase deficiency. The only treatment currently available is a bone-marrow transplant, but gene therapy offers hope for the future.
Medical dictionary. 2011.