Bone marrow flow cytometry revealed that 69.2% of these were mature B lymphocytes with immunophenotypes of CD19+, CD5+, CD20+dim, CD23+, CD200 partial+, CD79b (−), and FMC7 (−), whereas the levels of immunoglobulin kappa/lambda light chains in the cell membrane were not significant, suggesting the presence of CLL/SLL immunophenotypes (RMH-CLL score: 5 points). The gene discussed is FCER2; the disease is B-cell chronic lymphocytic leukemia.