OBJECTIVETo analyze the relationship between genotype and phenotype of homozygous hemoglobin Constant Spring (Hb CS) in Guangxi province, and to explore the reasons of missed diagnosis and the methods for screening and diagnosing.

METHODSScreening Hb CS by acetate fibrous membrane electrophoresis with benzidine staining. Gene mutation of homozygous Hb CS by polymerase chain reaction (PCR) and DNA sequencing.

RESULTSOut of the 9 patients, 4 had no clinical symptoms, 2 showed mild anemia and splenomegaly, 3 were jaundice. Hemoglobin levels were normal or mild anemia. MCVs were normal or reduced. Peripheral blood smear of all the patients displayed hypochromia, anisocytosis, poikilocytosis and target cells. The quantities of HbA(2) + Hb CS were 4.3% - 6.72%, while HbA(2) < 2%. Gene analysis confirmed the diagnosis of homozygous Hb CS.

CONCLUSIONThere was quite different in clinical symptoms, hematological parameters and hemoglobin quantifications for patients with homozygous Hb CS. They might have no clinical and hematological signs and looked like the phenotype of Hb H disease. Homozygous Hb CS was very easy to miss diagnosis. Gene analysis can be helpful.