The same mutation in humans causes immunodeficiency known as WHIM syndrome.18, 19, 20CXCR4WHIM mice display a similar selective dysregulation in the bone marrow B cell compartment as Wbp1l−/− mice with the reduction in B cell percentages that is most profound at the B cell progenitor level.20 They also show increase in marginal zone B cell percentages. Here, WBP1L is linked to WHIM syndrome.