Lee S Y, Phan M T T, Shin D J, Shin M G, Park J T, Shin J W, Yazer M H, Shin H B, Cho D
Department of Laboratory Medicine, Chonnam National University Medical School, Gwangju, Korea.
Center for Creative Biomedical Scientists, Chonnam National University, Gwangju, Korea.
Transfus Med. 2015 Oct;25(5):333-6. doi: 10.1111/tme.12229. Epub 2015 Jul 22.
Cis-AB, a rare ABO variant, is the result of a mutated ABO gene that produces a glycosyltransferase enzyme with dual A and B glycosyltransferase activity. It may lead to ABO discrepancies and a delay in establishing the blood group. To date, there have been no reports of a de novo mutation leading to a cis-AB allele.
Sequencing of the ABO gene using blood and hair follicle cells from the proposita were performed along with blood from her parents. To establish maternity and paternity, short tandem repeat (STR) analysis was also performed. The A and B enzyme activities of the novel enzyme were measured in an in vitro expression study.
A novel cis-AB allele arising from nucleotide substitution c.796A>G (p.M266V) in the B glycosyltransferase gene were discovered in the blood and hair follicle cells from the proposita, which was absent from her parents. In all 15 autosomal STR loci analysed, the probability of maternity and paternity were 0.999999 and 0.999989, respectively. The novel enzyme created 33.1% and 60.2% of A and B antigen compared to wild type A and B glycosyltransferases.
A novel mechanism leading to a cis-AB allele was discovered.
顺式AB是一种罕见的ABO血型变异，是ABO基因突变的结果，该突变产生一种具有A和B双糖基转移酶活性的糖基转移酶。它可能导致ABO血型鉴定不符以及血型确定延迟。迄今为止，尚无关于导致顺式AB等位基因的新发突变的报道。
对先证者的血液和毛囊细胞以及其父母的血液进行ABO基因测序。为确定亲子关系，还进行了短串联重复序列（STR）分析。在体外表达研究中测定了新型酶的A和B酶活性。
在先证者的血液和毛囊细胞中发现了一种由B糖基转移酶基因中的核苷酸替换c.796A>G（p.M266V）产生的新型顺式AB等位基因，其父母中不存在该等位基因。在分析的所有15个常染色体STR位点中，母系和父系的概率分别为0.999999和0.999989。与野生型A和B糖基转移酶相比，新型酶产生了A和B抗原的33.1%和60.2%。
发现了一种导致顺式AB等位基因的新机制。
