Conditional and B cell-specific deletion of Dnmt3a causes chronic lymphocytic leukemia [83] and the immunization of B cells deficient for Dnmt3a and Dnmt3b resulted in the antigen-specific expansion of B cells in germinal centers, plasma cell accumulation, and elevated levels of serum antibodies [84]. The gene discussed is DNMT3A; the disease is B-cell chronic lymphocytic leukemia.