First, we found 21 distinct mutations of myeloid neoplasm-associated genes in 11 out of 38 adult patients (28.9%) with chronic PRCA, and the 4 patients had driver mutations in TET2, DNMT3A or KDM6A. Second, despite its unknown relevance to disordered hematopoiesis, we found ambiguous and unlikely driver mutations in 4 patients. The gene discussed is TET2; the disease is pure red-cell aplasia.