Evaluation of Single Nucleotide Variants in Intron 1 of the ABO Gene as Diagnostic Markers for the A₁ Blood Group.

IF 1.9 4区医学 Q3 HEMATOLOGY

Transfusion Medicine and Hemotherapy Pub Date : 2023-01-18 eCollection Date: 2023-08-01 DOI:10.1159/000528683

Peter Bugert, Gabi Rink, Harald Klüter

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引用次数: 0

Abstract

Introduction: The molecular diagnosis of the A₁ blood group is based on the exclusion of ABO gene variants causing blood groups A₂, B, or O. A specific genetic marker for the A₁ blood group is still missing. Recently, long-read ABO sequencing revealed four sequence variations in intron 1 as promising markers for the ABO*A1 allele. Here, we evaluated the diagnostic values of the 4 variants in blood donors with regular and weak A phenotypes and genotypes.

Methods: ABO phenotype data (A, B, AB, or O) were taken from the blood donor files. The ABO genotypes (low resolution) were known from a previous study and included the variants c.261delG, c.802G>A, c.803G>C, and c.1061delC. ABO variant alleles (ABO*AW.06,*AW.08,*AW.09,*AW.13, *AW.30, and *A3.02) were identified in weak A donors by sequencing the ABO exons before. For genotyping of the ABO intron 1 variants rs532436, rs1554760445, rs507666, and rs2519093, we applied TaqMan assays with endpoint fluorescence detection according to a standard protocol. Genotypes of the variants were compared with the ABO phenotype and genotype. Evaluation of diagnostic performance included sensitivity, specificity, positive (PPV), and negative predictive value (NPV).

Results: In 1,330 blood donors with regular ABO phenotypes and genotypes, the intron 1 variants were significantly associated with the proposed A₁ blood group. In 15 donors, we found discrepancies to the genotype of at least one of the 4 variants. For the diagnosis of the ABO*A1 allele, the variants showed 98.79-99.48% sensitivity, 99.66-99.81% specificity, 98.80-99.31% PPV, and 99.66-99.86% NPV. Regarding the A phenotype, the diagnostic values were 99.02-99.41% sensitivity, 99.63-99.76% specificity, 99.41-99.61% PPV, and 99.39-99.63% NPV. The *A1 marker allele of all intron 1 variants was also associated with the *AW.06, *AW.13, and *AW.30 variants. Samples with *AW.08, *AW.09, and *A3.02 variants lacked this association.

Conclusion: The ABO intron 1 variants revealed significant association with the ABO*A1 allele and the A phenotype. However, the intron 1 genotype does not exclude variant alleles causing weak A phenotypes. With the introduction of reliable tag, single nucleotide variants for the A₁, A₂, B, and O blood groups and the genotyping instead of phenotyping of the ABO blood group are getting more feasible on a routine basis.

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评估ABO基因内含子1中的单核苷酸变体作为A1血型的诊断标记。

引言：A1血型的分子诊断是基于排除导致A2、B或O血型的ABO基因变体。A1血型的特定遗传标记仍然缺失。最近，长读ABO测序显示内含子1中的四个序列变异是ABO*A1等位基因的有希望的标记。在这里，我们评估了4种变体对具有常规和弱A表型和基因型的献血者的诊断价值。方法：从献血者档案中提取ABO表型数据（A、B、AB或O）。ABO基因型（低分辨率）是从先前的研究中已知的，包括变体c.261delG、c.802G>a、c.803G>c和c.1061delC。通过之前对ABO外显子进行测序，在弱a供体中鉴定出ABO变异等位基因（ABO*AW.06、*AW.08、*AW.09、*AW.13、*AW.30和*A3.02）。对于ABO内含子1变体rs532436、rs1554760445、rs507666和rs2519093的基因分型，我们根据标准方案应用具有终点荧光检测的TaqMan测定。将变体的基因型和ABO表型和基因型进行比较。诊断性能的评估包括敏感性、特异性、阳性（PPV）和阴性预测值（NPV）。结果：在1330名具有常规ABO表型和基因型的献血者中，内含子1变体与拟议的A1血型显著相关。在15名捐赠者中，我们发现4种变体中至少有一种的基因型存在差异。对于ABO*A1等位基因的诊断，变异显示出98.79-99.48%的敏感性、99.66-99.81%的特异性、98.80-99.31%的PPV和99.66-99.86%的NPV。关于A表型，诊断值为99.02-99.41%的敏感性、99.63-99.76%的特异性、99.41-99.61%的PPV和99.39-99.63%的NPV。所有内含子1变体的*A1标记等位基因也与*AW.06、*AW.13和*AW.30变体相关。带有*AW.08、*AW.09和*A3.02变体的样本缺乏这种关联。结论：ABO内含子1变异体与ABO*A1等位基因和A表型有显著相关性。然而，内含子1基因型并不排除引起弱A表型的变异等位基因。随着可靠标签的引入，A1、A2、B和O血型的单核苷酸变体以及ABO血型的基因分型而不是表型分型在常规基础上变得更加可行。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Transfusion Medicine and Hemotherapy 医学-免疫学

CiteScore

4.00

自引率

9.10%

发文量

审稿时长

6-12 weeks

期刊介绍： This journal is devoted to all areas of transfusion medicine. These include the quality and security of blood products, therapy with blood components and plasma derivatives, transfusion-related questions in transplantation, stem cell manipulation, therapeutic and diagnostic problems of homeostasis, immuno-hematological investigations, and legal aspects of the production of blood products as well as hemotherapy. Both comprehensive reviews and primary publications that detail the newest work in transfusion medicine and hemotherapy promote the international exchange of knowledge within these disciplines. Consistent with this goal, continuing clinical education is also specifically addressed.