Primary immunodeficiencies concerning CORO1A CD27, CTPS1, DOCK8, DOCK2, ITK, MST1, MAGT1, MVK, ORAI1 and STIM1 gene defects triggered by EBV infection frequently occur in young infants, which results in B lymphoproliferation (Bode et al. 2015). The gene discussed is CTPS1; the disease is inborn error of immunity.