Tadmouri G O, Yüksel L, Başak A N
Department of Molecular Biology and Genetics, Boğaziçi University, Bebek, Istanbul, Turkey.
Am J Hematol. 1998 Sep;59(1):83-6. doi: 10.1002/(sici)1096-8652(199809)59:1<83::aid-ajh16>3.0.co;2-2.
Beta-thalassemia and sickle cell disease (SCD) are common disorders in Turkey. Compound heterozygosity for these two disorders (betaS/beta-thalassemia) is encountered frequently. In this report we present hematological and molecular data of two Turkish siblings with betaS/beta(del)-thalassemia caused by a 290 base pair (bp) deletion and associated with increased levels of hemoglobin A2 (HbA2) and hemoglobin F (HbF). Clinical analysis of the two patients showed a mild course of the disease. Haplotypic factors involved in increasing the levels of HbF were analyzed. The two patients showed no changes from the normal sequences at the XmnI site of Ggamma-globin promoter and the (AT)xTy microsatellite 5' to the beta-globin mRNA cap site. The removal of the region between positions -125 to +78 relative to the beta-globin gene mRNA cap site by the 290 bp deletion is thought to allow the beta-locus control region to interact with the promoters of the delta- and gamma-globin genes, leading to increased HbA2 and HbF levels.
β地中海贫血和镰状细胞病（SCD）在土耳其是常见疾病。这两种疾病的复合杂合子（βS/β地中海贫血）很常见。在本报告中，我们展示了两名土耳其同胞的血液学和分子数据，他们患有由290个碱基对（bp）缺失引起的βS/β（del）-地中海贫血，并伴有血红蛋白A2（HbA2）和血红蛋白F（HbF）水平升高。对这两名患者的临床分析显示疾病进程较轻。分析了参与提高HbF水平的单倍型因素。这两名患者在Gγ-珠蛋白启动子的XmnI位点以及β-珠蛋白mRNA帽位点5'端的（AT）xTy微卫星处的正常序列没有变化。290 bp缺失导致相对于β-珠蛋白基因mRNA帽位点-125至+78位之间区域的缺失，被认为使得β基因座控制区能够与δ-和γ-珠蛋白基因的启动子相互作用，从而导致HbA2和HbF水平升高。
