One patient with clonal TCR rearrangement carried concurrent CDKN2A and EZH2 mutations, suggesting two possibilities: 1) the presence of clonal TCRB gene rearrangements is not always equivalent to T-cell malignancy because non-neoplastic diseases (benign monoclonal γ-globulin disease, immunodeficient diseases associated with Epstein-Barr virus infections or autoimmune diseases) may also exhibit the clonal peak pattern [41, 42]; and 2) clonal TCR rearrangements with somatic mutations may suggest early stages of T-cell malignancy. The gene discussed is EZH2; the disease is immunodeficiency disease.