Confirming the relevance of RHO proteins in hematopoietic cell development and disease, by using WES, several authors have recently established the pathogenicity of various dominantly acting mutations in RAC2, which cause pediatric immunodeficiencies affecting T, B, and myeloid cells (including Hsu et al., 2019; Sharapova et al., 2019; Lagresle-Peyrou et al., 2020). Here, RAC2 is linked to Immunodeficiency.