Cells overexpressing CXCR4E343D have no functional changes compared with wild-type CXCR4, whereas cells overexpressing CXCR4E343K, CXCR4E343R or CXCR4E343A show increased cell migration, prolonged phosphorylation of ERK1/2, p38, JNK1/2/3 and increased activation of PI3K/AKT/NF-κB signal pathway, that is, all these mutants reproduce the in vitro signaling events associated with WHIM syndrome (108). The gene discussed is CXCR4; the disease is WHIM syndrome.