Myelodysplastic syndrome (MDS) is a group of heterogeneous diseases derived from hematopoietic stem cells characterized by hemolytic anemia and high risk of conversion to acute leukemia. MDS is an age-related disease in which approximately 80% of patients are over 60years of age, male and female. Anemia is the most common clinical condition, and many patients are also associated with infection and bleeding. When the amount of alpha globin synthesis is insufficient, the remaining beta chain forms tetramer beta 4, i.e. HbH. The latter forms a precipitate in red blood cells, leading to hemolytic anemia, called HbH disease, the majority of which is congenital, a small number of patients with myelodysplastic syndrome and acute myeloid leukemia may appear HbH (called acquired HbH disease). We reported a 71years old male patient diagnosed as myelodysplastic syndromes (MDS) in our hospital. The patient has a negative alpha-thalassemia gene test. The H band is detected by hemoglobin electrophoresis. This article analyzed and discussed this case with MDS, as well reviewed MDS. (C) 2020 Published by Elsevier Masson SAS on behalf of Societe francaise de transfusion sanguine(SFTS).