Background:
The aim of this study was to investigate the prevalence, clinical and laboratory findings of hereditary hemolytic anemia (HHA) in Korea from 1997 to 2006 and to develop the appropriate diagnostic approach for HHA.
Methods:
By the use of questionnaires, information on the clinical and laboratory findings ofHHA diagnosed from 1997 to 2006 in Korea was collected and analyzed retrospectively. A total of 431 cases were enrolled in this study from 46 departments of 35 hospitals.
Results:
The overall frequency of HHA did not change through the 10-year period for pediatrics but did show an increasing tendency for internal medicine. The overall male to female sex ratio did not show sex predominance (1.17：1), but a significant male predominance with a ratio of 1.49：1 was seen for pediatrics while a significant female predominance with a ratio of 1：1.97 was seen forinternal medicine. Of the total cases, 74.2% (282/431) were diagnosed before the age of 15 years. The etiologies of HHA were classified as red cell membrane defects, hemoglobinopathies, red cell enzyme deficiencies and unknown causes. There were 382 cases (88.6%) of red cell membrane defects with 376 cases (87.2%) of hereditary spherocytosis and 6 cases (1.4%) of hereditary elliptocytosis, 20 cases (4.6%) of hemoglobinopathies with 18 cases (4.2%) of β-thalassemia, a case (0.2%) of α-thalassemia and a case (0.2%) of Hemoglobin Madrid, 7 cases (1.6%) of red cell enzyme deficiencies with 5 cases (1.2%) of glucose-6- phosphate dehydrogenase (G-6-PD) deficiency, a case (0.2%) of pyruvate kinase (PK) deficiency and a case (0.2%) of enolase deficiency, and 22 cases (5.1%) of unknown causes. The most common chief complaint in pediatric patients was pallor and that in adult patients was jaundice. In the red cell membrane defect group of patients, the level of hemoglobin was significantly higher than in adult patients. The mean corpuscular volume, mean corpuscular hemoglobin, corrected reticulocyte count, total and indirect bilirubin level and lactate dehydrogenase levels in the hemoglobinopathy group of patients were significantly lower than the values in the red cell membrane defect group of patients. The mean concentration of G-6-PD was 0.8±0.7U/1012RBC in the G-6-PD deficient patients, PK was 1.7U/1010 RBC in the PK deficient patient, and the level of enolase was 0.04U/g of Hb in the enolase deficient patient.
Conclusion:
The most prevalent cause of HHA in Korea during 1997 to 2006 was hereditary spherocytosis, but HHA by other causes such as hemoglobinopathy and red cell enzyme deficiency gradually increased with the development of molecular diagnostic methods and increasing general interest. However, the etiologies of HHA need to be pursued further in 5.1% of the patients. An systematic standard diagnostic approach is needed in a nationwide prospective study for correct diagnoses and appropriate management of HHA.

Keywords: Hereditary hemolytic anemia, Korea, Frequency, Etiologies