Olsson M L, Chester M A
Department of Transfusion Medicine, Institute of Laboratory Medicine, Lund University, SE-221 85 Lund, Sweden.
Transfus Med. 2001 Aug;11(4):295-313. doi: 10.1046/j.1365-3148.2001.00320.x.
The blood group ABO gene codes for a glycosyltransferase that adds the ultimate monosaccharide to a glycoconjugate and forms the A or B blood group specific antigen. The DNA structure of the three major alleles of the human blood group ABO system was first described in 1990. This review describes the subsequent developments, including the increasing number of variants of these common alleles and the underlying mutations thought to be responsible for the occurrence of some of the weak subgroups of blood group A and B. Several inactive (O) alleles are also now known. Our knowledge of the DNA sequence of the normal A and B alleles and of the rare and intriguing cisAB and B(A) phenotypes has resulted in plausible explanations for these. Allelic variations outside the translated exons have been investigated and resulted in detection of lineage-specific intron mutations and the discovery of an enhancer VNTR region affecting the rate of transcription at this locus. The occurrence of hybrid alleles can also explain hitherto abnormal inheritance in some pedigrees. The detection of hybrid alleles has been made possible by the presence of numerous polymorphisms found in the various ABO alleles. The role of chi (chi) sequences is discussed. Finally, the various genotyping methods available are summarized and their advantages and limitations are analysed in the light of the increasing allelic variation.
血型ABO基因编码一种糖基转移酶，该酶将最终的单糖添加到糖缀合物上，形成A或B血型特异性抗原。人类血型ABO系统的三个主要等位基因的DNA结构于1990年首次被描述。本综述描述了随后的进展，包括这些常见等位基因变体数量的增加以及被认为是导致A和B血型一些弱亚型出现的潜在突变。现在也已知几种无活性（O）等位基因。我们对正常A和B等位基因以及罕见且有趣的顺式AB和B（A）表型的DNA序列的了解，为这些现象提供了合理的解释。已对翻译外显子之外的等位基因变异进行了研究，结果检测到谱系特异性内含子突变，并发现了一个影响该基因座转录速率的增强子VNTR区域。杂交等位基因的出现也可以解释一些家系中迄今异常的遗传现象。由于在各种ABO等位基因中发现了大量多态性，使得杂交等位基因的检测成为可能。讨论了χ（chi）序列的作用。最后，总结了现有的各种基因分型方法，并根据等位基因变异的增加分析了它们的优缺点。
