Abstract
This study is a prospective evaluation of children with Severe Combined Immune Deficiency (SCID) who are treated under a variety of protocols used by participating institutions. In order to determine the patient, recipient and transplant-related variables that are most important in determining outcome, study investigators will uniformly collect pre-, post- and peri-transplant (or other treatment) information on all children enrolled into this study. Children will be divided into three strata: - Stratum A: Typical SCID with virtual absence of autologous T cells and poor T cell function - Stratum B: Atypical SCID (leaky SCID, Omenn syndrome and reticular dysgenesis with limited T cell diversity or number and reduced function), and - Stratum C: ADA deficient SCID and XSCID patients receiving alternative therapy including PEG-ADA ERT or gene therapy. Each Group/Cohort Stratum will be analyzed separately.