Evaluation of newborn screening for severe combined immunodeficiency (SCID).

Abstract

Important features about a screening programme for newborn infants are that it should accurately, without too many false positives, detect a disease that is serious, where effective management is readily available and early presymptomatic detection and intervention should reduce morbidity and mortality. The screening test must be applicable to the general neonatal population and the whole programme should have an acceptable cost, relative to the potential benefit. A definitive followup test that distinguishes true positives from false positives should be readily available. Following diagnosis, treatment should be instituted in a timely manner. It is essential that the programme is subjected to appropriate monitoring and quality assurance to ensure that the intended outcome is delivered. Most diseases detected by newborn screening are rare, and severe combined immunodeficiency (SCID) is no exception. Affecting approximately 14 infants a year in England, SCID is caused by mutations in one of a number of genes responsible for development of T-lymphocytes. Affected infants appear well at birth but present by a few months of age with recurrent or persistent infection and failure to thrive. The condition is usually fatal by 12–18 months of age without bone marrow transplantation.1 By measuring ‘waste’ DNA, produced during lymphocyte receptor formation (TRECs), on the newborn screening blood spot card, SCID can be detected and confirmed by flow cytometry.2 To find out how devastating the disease is for a family, we have asked Rebecca to tell us about her experience. ‘I’m Rebecca and I’m a parent of three …