Myelodysplastic syndrome with ring chromosomes in a case of dehydrated hereditary stomatocytosis 1 (DHS1).

We report here a case of myelodysplastic syndrome (MDS) that developed in a 60-year-old female with dehydrated hereditary stomatocytosis 1 (DHS1) with PIEZO1 gene mutation (p. E2496ELE). The patient had a non-transfused status until the age of 60, when her anemia progressed. Bone marrow examination revealed multilineage MDS (no increase in blasts) with a non-complex karyotype showing two types of ring chromosomes (RCs) confirmed by the G-banding method. A targeted next-generation sequencing (NGS) assay revealed Tet methylcytosine dioxygenase 2 (TET2) gene mutations (p. Y592fs and p. R1261C), and 9p amplification was noted. Spectral karyotyping determined that RCs were derived from chromosome 9, suggesting that the JAK2 gene might have played a role in MDS development. As a treatment, we plan to give a hypomethylating agent.