XIST and lymphoproliferative syndrome: In further support of the importance of correct XIST localisation in T cells, when Cip1-interacting zinc finger protein (CIZ1) (a protein recruited to the Xi by XIST) is knocked out, Ciz1 null mice develop fully penetrant female-specific lymphoproliferative disorder, and Xist localisation is disrupted in splenic T cells in the absence of CIZ1 [40].