METHODS: The ABO blood group of the sample was determined, in addition with the activity of blood group glycosyltransferase and blood group secretory substances. Sanger sequencing was adopted to analyze the genotype of the blood group.
RESULTS: The proband was identified as A subtype (non-secretory type), with no detectable activities of a 1, 3-N-acetylgalactosyltransferase. DNA sequencing has identified a number of mutations including nt.261del/G and 297A/A of exon 6, and nt.467C/T, 806T/C and 1009A/G of exon 7. Clone sequencing has confirmed that the nt.806T>C exists at one allele and was a novel mutation. The proband genotype was A205/Onew (806T>C). The nt.806T>C of the exon 7 was confirmed to be a novel mutation, which was given a GenBank accession number KP341759. Family study showed that the genotype of the proband\'s father was Onew (806T>C)/O02, and that of his mother was A101/A205. The novel mutation of the proband has derived from his father.
CONCLUSIONS: The reduced A antigenicity of the sample was due to the A205 subtype allele and the presence of a novel O allele.
方法:测定样本的ABO血型,另外还具有血型糖基转移酶和血型分泌物质的活性。采取Sanger测序剖析血型的基因型。
结果:先证者被鉴定为A亚型(非分泌型),没有可检测的1,3-N-乙酰半乳糖基转移酶活性。DNA测序已经确定了许多突变,包括外显子6的nt.261del/G和297A/A,以及nt.467C/T,外显子7的806T/C和1009A/G。克隆测序已经证实nt.806T>C存在于一个等位基因处并且是新的突变。先证者基因型为A205/Onew(806T>C)。外显子7的nt.806T>C被证实是一个新的突变,它被授予GenBank登录号KP341759。家庭研究表明,先证者父亲的基因型为Onew(806T>C)/O02,母亲的基因型为A101/A205。先证者的新颖突变源于他的父亲。
结论:样品的A抗原性降低是由于A205亚型等位基因和新的O等位基因的存在。