Analysis of weak expression of A antigen induced by ABO gene mutation

doi:10.16150/j.1671-2870.2024.06.009

Abstract

Abstract:

Objective This study aims to perform blood group genotyping on patients with weak antigen expression detected by ABO serology and analyze the causes of weak antigen expression. Methods Serological detection was carried out by the microcolumn gel method. Blood group genotyping was conducted by PCR combined with direct sequencing. The enhancer, promoter, exons 1-7, and adjacent intron regions of the ABO blood group gene in the patients were tested. The software PolyPhen-2 was used to predict the nucleotide function of mutations and to generate a 3D structural model. Results In one male patient, the red blood cells showed weak agglutination with anti-A antibody (2+) and agglutination with anti-B antibody (4+). The patient’s serum showed weak agglutination with A1 cells (2+), and no agglutination with B cells and O cells. The serological phenotype of the ABO blood group was A_weakB, with both the direct antiglobulin test and antibody screening test being negative. The results of DNA sequencing showed that there were c.297 A>G mutation in exon 6, and c.526 C>G, c.657 C>T, c.703 G>A, c.796 C>A, c.803 G>C, c.930 G>A and c.940 A>G mutations in exon 7. According to the International Blood Transfusion Association database, the c.940 A>G mutation leads to p.Lys314Glu mutation in the ABO gene-encoded glycosyl transferase A (GTA), resulting in decreased A enzyme activity. The patient’s genotype was ABO*AW.37/B.01. Conclusions In this patient, exon 7 of the ABO blood group gene has a c.940 A>G mutation. This mutation site can change the encoded amino acid, namely p.Lys314Glu, resul-ting in weak expression of A antigen.

Key words: ABO blood group, Genotype, Exon, Weak antigen expression

CLC Number:

R457.11

GU Yuwei, WANG Chengyun, GU Ping, PAN Qiuhui, WANG Jing. Analysis of weak expression of A antigen induced by ABO gene mutation[J]. Journal of Diagnostics Concepts & Practice, 2024, 23(06): 619-623.

Figures/Tables 4

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References 21

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Primer name	Primer sequence（5′→3′）	Amplification fragment length/bp
Promoter-E1	F:CGGGAGACAGGGTGTCAAG R:TCGGGCGGTAGGTGCTGAA	731
Enhancer	F:CCCCATCCATAGTCAGATAAGC R:AAAGCAGCCAGCCAGTGTT	724
ABO-E2	F:GAGAAGGAGGGTGAGTGATG R:AGTGAGATGAGCCTGTTGC	323
ABO-E3	F:GTCCCAGAACCAAGAGTGA R:TCCAGAGGTATCCAGGTGA	616
ABO-E4	F:AAGACCAACATCCCAAGAA R:GAGCCACAGGAGGAAAGAG	624
ABO-E5	F:TGCTTACCTGCATCCCACGCT R:TCAAGGAAACCGCCCTCTAAT	572
ABO-E6	F:CATTTGCCTCTGGTTGGTTT R:CTGGAGAAGGAGCTGGGTTT	522
ABO-E7	F:TCTGCTGCTCTAAGCCTTCC R:CCCGTTCTGCTAAAACCAAG	878

Serological identification results	Anti-A	Anti-B	A1c	Bc	Oc	DAT	IAT	ABS
患儿	2+	4+	2+	-	-	-	-	-
AB型对照	4+	4+	-	-	-	-	-	-