RAC2 loss-of-function mutation in 2 siblings with characteristics of common variable immunodeficiency

Common variable immunodeficiency (CVID) represents a heterogeneous group of disorders with variable immunologic and clinical phenotypic features, including hypogammaglobulinemia, recurrent infections, and autoimmunity.1 Over the past decades, a number of genetic defects have been identified that are associated with CVID. However, these alterations only account for the cause of a minority of CVID cases (<15%).1 In this article we present a novel genetic defect in the Ras-related C3 botulinum toxin substrate 2 (RAC2) gene in 2 siblings previously given a diagnosis of CVID.