Oner C, Oner R, Balkan H, Gürgey A, Yalçin A, Avcu F, Altay C
Hacettepe University, Science Faculty, Department of Molecular Biology, Beytepe, Ankara, Turkey.
Br J Haematol. 1997 Feb;96(2):229-34. doi: 10.1046/j.1365-2141.1997.d01-2022.x.
Two unrelated (delta beta)(0)-thalassaemia patients from Southern Turkey are presented. DNA studies indicated that both of them are homozygous for the Turkish type of (delta beta)(0)-thalassaemia characterized by one large deletion of 11.5 kb including the delta and beta globin genes at the 5' end and one small deletion of 1.6 kb at the 3' end, which are separated by an inverted 7.6 kb long DNA segment that includes L1 repetitive sequence. In the present study a PCR-based method was performed to produce a unique deletion-specific product and subjected to sequence analysis for the determination of the breakpoint. DNA polymorphisms in the beta-globin gene cluster of deletion-inversion type of (delta beta)(0)-thalassaemia, IVS-I-6 and beta-39 globin genes were examined. Analysis of sequence variations in regulatory regions including the 5' hypersensitive site-2 of the locus control region (LCR), the delta, (G)gamma and (A)gamma 5' flanking regions and the second intervening sequence (IVS-II) of (A)gamma and (G)gamma genes indicated the presence of close similarities between the chromosome carrying the Turkish form of deletion-inversion (delta beta)(0)-thalassaemia and the chromosome associated with beta-39 nonsense mutation in haplotype II. These two chromosomes are characterized by the presence of a 4 base pair deletion in the (A)gamma(T) globin gene promoter. A C --> T alteration at position -199 5' to the delta gene was also found to be associated with the Turkish type of (delta beta)(0)-thalassaemia and beta-39 chromosome.
本文报告了来自土耳其南部的两名非亲缘关系的（δβ）（0）-地中海贫血患者。DNA研究表明，他们两人均为土耳其型（δβ）（0）-地中海贫血的纯合子，其特征是在5'端有一个11.5 kb的大缺失，包括δ和β珠蛋白基因，在3'端有一个1.6 kb的小缺失，这两个缺失由一个包含L1重复序列的7.6 kb长的反向DNA片段隔开。在本研究中，采用基于PCR的方法产生独特的缺失特异性产物，并进行序列分析以确定断点。对缺失-倒位型（δβ）（0）-地中海贫血、IVS-I-6和β-39珠蛋白基因的β-珠蛋白基因簇中的DNA多态性进行了检测。对包括基因座控制区（LCR）的5'超敏位点-2、δ、（G）γ和（A）γ 5'侧翼区以及（A）γ和（G）γ基因的第二内含子序列（IVS-II）在内的调控区序列变异的分析表明，携带土耳其型缺失-倒位（δβ）（0）-地中海贫血的染色体与单倍型II中与β-39无义突变相关的染色体之间存在密切相似性。这两条染色体的特征是（A）γ（T）珠蛋白基因启动子中有一个4碱基对的缺失。还发现δ基因5'端-199位的C→T改变与土耳其型（δβ）（0）-地中海贫血和β-39染色体相关。
