The Wisconsin approach to newborn screening for severe combined immunodeficiency

Severe combined immunodeficiency (SCID) is a life-threatening disease of infants that is curable with hematopoietic cell transplantation if detected early. Population-based screening for SCID using the T-cell receptor excision circle (TREC) assay began in Wisconsin in 2008; 5 infants with SCID or other forms of severe T-cell lymphopenia (TCL) have been detected, and no infants with SCID have been missed. This review will provide an overview of the TREC screening assay and an update of the findings from Wisconsin on all infants screened from January 1, 2008, until December 31, 2010. Importantly, we give practical recommendations regarding newborn population-based screening using the TREC assay, including the evaluation and care of infants detected.