LAUSR

KREC (kappa-deleting recombining excision circles) quantification has been used in newborn screening programs to identify infants with X-linked agammaglobulinemia (XLA) and other B cell associated forms of primary immunodeficiency disease (PID). We evaluated KREC quantification in patients with XLA at various time points throughout life in order to determine the utility of this assay beyond the newborn period. We found that levels remain consistently low or absent throughout life, thus demonstrating that KREC quantification enables identification of patients with XLA and is a useful diagnostic tool in the newborn period, childhood and adulthood. This article is protected by copyright. All rights reserved.