Abnormal hemoglobins found in Hunan.

OBJECTIVE: To summarize the results of general survey, primary structure analysis and related functional studies of abnormal hemoglobins (Hbs) found in Hunan Province.

DATA SOURCES: International Hb journals, Chinese biochemical and biomedical journals and other articles relevant to hematology.

STUDY SELECTION: All Hb variants found in Hunan and identified by primary structure analysis during 1980 - 1991 were included.

DATA EXTRACTION: Data concerning 11 types of Hb variants found in 3 districts and 7 counties in Hunan Province were briefly documented. Their frequencies of occurrence were calculated and their distributions among Han, Yao, Tujia and Dong ethnic groups were listed.

RESULTS: Thirty-six cases with abnormal Hb were identified out of 7412 individuals screened in Hunan. 11 different types of Hb variants were recognized by primary structure analysis in 19 propositi along with their family members, including 5 alpha-chain variants, 4 beta-chain variants, 1 delta-chain variant and 1 delta-beta chain fusion variant. Oxygen equilibrium characteristics, reaction dynamics, the rate of globin chain synthesis (RGCS), morphology observation by electron microscopy and DNA analysis were all used in the functional studies of hemoglobinopathies.

CONCLUSIONS: The average incidence of abnormal Hbs in Hunan is 0.486%. In Jianghua County, whose inhabitants are mostly of the Yao ethnic group, the incidence is significantly higher (1.09%). Hb Jianghua [beta120(GH3) Lys-->lle] and Hb Shuangfeng (SF) [alpha27(B8) Glu-->Lys] were two new variants first reported in international literature; whereas Hb Lille [alpha74(EF3) Asp-->Ala], HbA(2) Flatbush [delta22(B4) Ala-->Glu] and Hb Lepore-Boston [delta87(F3)-beta116(G18)] were the first three instances to be found in China. Hb SF displayed an oxygen affinity 1.5-fold higher than that of HbA at pH 7.4 and 25 degrees C with its oxygen equilibrium curve shifted to the left. Reticulocytes of Hb SF heterozygote showed unbalanced RGCS, quite similar to that found in beta-thalassemia minor. Erythrocytes of Hb SF heterozygote were changed to spherocytes and began to lyse after incubation with sodium salicylate or sulfadiazine (pH 7.4, 37 degrees C) for 2 - 4 h. These findings explained the sudden attack of hemolytic anemia provoked by two drugs in Hb SF propositus. The genotype of a patient with Hb Q-H disease is identified as -,-/-,alpha(Q) by DNA restriction mapping.