CXCR4 and WHIM syndrome: Orsini et al. found that phosphorylation of S338/339 were essential for homologous desensitization [30–32], the mutation of CXCR4E343K found in a family with WHIM syndrome does not introduce a loss of any single phosphorylation site in the C-terminus of CXCR4, but the mutation only is close to phosphorylation residues at S346/347 and S338/339.