OBJECTIVE: To explore the serological characteristics of ABO blood group and molecular genetic mechanism for a Chinese pedigree with cisAB09 subtype. METHODS: A pedigree undergoing ABO blood group examination at the Department of Transfusion, Zhongshan Hospital Affiliated to Xiamen University on February 2, 2022 was selected as the study subjects. Serological assay was carried out to determine the ABO blood group of the proband and his family members. Activities of A and B glycosyltransferases in the plasma of the proband and his mother were measured with an enzymatic assay. Expression of A and B antigens on the red blood cells of the proband was analyzed by flow cytometry. Peripheral blood samples of the proband and his family members were collected. Following extraction of genomic DNA, exons 1 to 7 of the ABO gene and their flanking introns were sequenced, and Sanger sequencing of exon 7 was carried out for the proband, his elder daughter and mother. RESULTS: The results of serological assay suggested that the proband and his elder daughter and mother had an A2B phenotype, whilst his wife and younger daughter had an O phenotype. Measurement of plasma A and B glycosyltransferase activity suggested that the titers of B-glycosyltransferase activity were 32 and 256 for the proband and his mother, which were respectively below and above that of A1B phenotype-positive controls (128). Flow cytometry analysis showed that the expression of A antigen on the red blood cell surface of the proband has decreased, whilst the expression of B antigen was normal. Genetic sequencing confirmed that, in addition to an ABO*B.01 allele, the proband, his elder daughter and mother have harbored a c.796A>G variant in exon 7, which has resulted in substitution of the methionine at 266th position of the B-glycosyltransferase by valine and conformed to the characteristics of ABO*cisAB.09 allele. The genotypes of the proband and his elder daughter were determined as ABO*cisAB.09/ABO*O.01.01, his mother was ABO*cisAB.09/ABO*B.01, and his wife and younger daughter were ABO*O.01.01/ABO*O.01.01. CONCLUSION The c.796A>G variant of the ABO*B.01 allele has resulted in an amino acid substitution p.Met266Val, which probably underlay the cisAB09 subtype. The ABO*cisA B.09 allele encodes a special glycosyltransferase which can synthesize normal level of B antigen and low level of A antigen on the red blood cells.
Humans ; ABO Blood-Group System/genetics* ; Pedigree ; East Asian People ; Genotype ; Phenotype ; Alleles ; Glycosyltransferases/genetics* ; Molecular Biology

OBJECTIVE: In this study, the results of forward and reverse blood typing of a male patient diagnosed as bronchiectasis were inconsistent, which were type O and type A respectively. Multiple experiments including genotyping and sequencing and family investigation were carried out to determine the subtype of ABO blood group and explore the serological characteristics of this subtype. METHODS: Standard serological techniques were used to conduct forward and reverse typing, reverse blood typing enhancement test, H antigen identification, absorption-elution test, salivary blood group substances test, and PCR-SSP method for ABO genotyping and exon 6 and 7 sequencing. RESULTS: The proband's blood group was type O by forward typing, but antigen A could be detected by absorption-elution test, anti-A1 could be detected by reverse blood typing enhancement test, it was found that there was substance H but no substance A in saliva, and the serological characteristics were consistent with Ael subtype. Gene sequencing analysis showed that there was a c.625T>G base substitution on the basis of A102, which had never been reported before. Family survey showed that c.625T>G base substitution appeared in three generations of the family. CONCLUSION In this study, a new subtype A with Ael serological characteristics caused by c.625T>G mutation was identified. c.625T>G base substitution results in the weakening of A antigen, and this mutation can be stably passed down to future generations.
Humans ; Male ; Genotype ; Phenotype ; Alleles ; Mutation ; ABO Blood-Group System/genetics*

OBJECTIVE: To explore the molecular mechanism for an individual with Bweak subtype. METHODS: Serological methods were used to identify the proband's phenotype. In vitro enzyme activity test was used to determine the activity of B-glycosyltransferase (GTB) in her serum. The genotype was determined by PCR amplification and direct sequencing of exons 5 to 7 and flanking sequences of the ABO gene. T-A cloning technology was used to isolate the haploids. The primary physical and chemical properties and secondary structure of the protein were analyzed with the ProtParam and PSIPRED software. Three software, including PolyPhen-2, SIFT, and PROVEAN, was used to analyze the effect of missense variant on the protein. RESULTS: Serological results showed that the proband's phenotype was Bweak subtype with anti-B antibodies presented in her serum. In vitro enzyme activity assay showed that the GTB activity of the subject was significantly reduced. Analysis of the haploid sequence revealed a c.398T>C missense variant on the B allele, which resulted in a novel B allele. The 398T>C variant has caused a p.Phe133S substitution at position 133 of the GTB protein. Based on bioinformatic analysis, the amino acid substitution had no obvious effect on the primary and secondary structure of the protein, but the thermodynamic energy of the variant protein has increased to 6.07 kcal/mol, which can severely reduce the protein stability. Meanwhile, bioinformatic analysis also predicted that the missense variant was harmful to the protein function. CONCLUSION The weak expression of the Bweak subtype may be attributed to the novel allele of ABO*B.01-398C. Bioinformatic analysis is helpful for predicting the changes in protein structure and function.
Female ; Animals ; ABO Blood-Group System/genetics* ; Phenotype ; Genotype ; Exons ; Alleles

Objective To investigate the effect of blood group serology and polymerase chain reaction with sequence-specific primers (PCR-SSP) on identification and genotyping of ambiguous ABO blood group. Methods Eighty suspicious ABO blood group samples were identified by serology and polymerase chain reaction with sequence-specific primers (PCR-SSP). The final blood group type and the strategy of the transfusion of each case were determined according to the results of serology and PCR-SSP. Results 40 cases were confirmed to be subtypes, and the remaining 40 cases were normal types with weakened antigens or missing antibodies due to other reasons. The results of molecular genetic blood group typing based on PCR-SSP were 41 cases of subtypes (There were 3 discrepancies between two methods: one was Ael identified by serological methods, while its gene type was O2O2; one was common type O, while its gene type was BO1; one was type A, while its gene type was AB.) and 39 cases of normal ones. Conclusion Genotyping technology combined with serological typing has an important significance in identification of ABO blood groups.
ABO Blood-Group System/genetics* ; Genotype ; Polymerase Chain Reaction ; Antibodies ; DNA Primers

OBJECTIVE: To identify and analysis three ABO variant Bw subtypes. METHODS: Serological assays were carried out to identify the ABO blood group of the proband. ABO gene was identified by Sanger sequencing. RESULTS: The genotype of three individuals are ABO*Bw.11/0.01.02, ABO*Bw.12/0.01.01, ABO*Bw.34/A1.02, receptively. Sequencing results showed that there were c.695T>C, c.278C>T, c.889G>A, resulting in variants in Leu232Pro, Pro93Leu and Glu297Lys, receptively. CONCLUSION Bw11, Bw12 and Bw34 subgroups were identified, and gene testing can be used as a supplement to determine the ABO blood group subtypes.
ABO Blood-Group System/genetics* ; Alleles ; Blood Grouping and Crossmatching ; Exons ; Genotype ; Humans ; Phenotype ; Sequence Analysis

OBJECTIVE: To analyze the molecular characteristics of a ABO subgroup. METHODS: The ABO phenotype was determined with the tube method. Exons of the ABO gene were analyzed by Sanger sequencing, and haplotypes of exons 6 and 7 were analyzed by cloning sequencing. RESULTS: By forward typing, the red blood cells showed 3+ agglutination reaction with anti-A and 4+ agglutination with anti-B. A weak reaction with A1 cells and no agglutination reaction with B, O cells by the reverse typing. Sequencing results showed heterozygosity including c.297A>G, c.467C>T, c.526C>G, c.608A>G, c.657C>T, c.703G>A, c.796C>A, c.803G>C, c.930G>A. Cloning sequencing revealed a c.608A>G variant in the A allele compared with the ABO*A1.02. CONCLUSION A new variant site of subtype A of c.608G variation has been identified.
ABO Blood-Group System/genetics* ; Alleles ; Exons ; Genotype ; Heterozygote ; Phenotype

OBJECTIVE: To explore the genetic mechanism underlying a case with para-Bombay phenotype. METHODS: The ABO and Lewis phenotype were identified with serological methods. The coding regions of exons 6 and 7 of the ABO and FUT1 genes were amplified with PCR and directly sequenced. Haploid sequence analysis was carried out on the variant sites of the FUT1 gene. RESULTS: Serological analysis confirmed that the proband has a rare para-Bombay phenotype. Direct sequencing revealed that he was a B.01/O.01.02 heterozygote for the ABO gene, and had heterozygous deletion for the 768 and 881-882 sites of the FUT1 gene. Further haploid analysis showed that the c.881_882delTT deletion has occurred in one haploid while c.768delC was present in the other haploid. The proband was therefore determined as a FUT1*01N.13/01N.20 heterozygote, which have resulted in frameshift in polypeptide chain p.Phe294Cysfs*40 and p.Val257Phefs*23, respectively. CONCLUSION A rare bi-allelic heterozygous deletion of para-Bombay phenotype has been identified in a blood donor. The c.881_882delTT and c.768delC deletions may decrease the activity of α-1,2-fucosyltransferase.
Animals ; Male ; ABO Blood-Group System/genetics* ; Alleles ; Fucosyltransferases/genetics* ; Genotype ; Heterozygote ; Mutation ; Phenotype ; Humans

OBJECTIVE: Through analysis of ABO blood group gene typing technology, to assist in the identification of difficult clinical serological specimens. METHODS: A total of 10 forwardreverse typing ambiguous samples were collected from January 2021 to August 2021 in our hospital.ABO genotypes were analysed by gene sequencing. RESULTS: The genotypes of 10 ABO ambiguous blood group samples were A102/BW11, A102/BW12, O02/O02, A102/B303, A102/B101, BW11/O02, B101/O04, BW11/O01, BW11/O01, A101/O02, respectively. The genotype results of 6 cases was consistent with the serological phenotype, and the serological phenotype of 4 cases were different from the geno sequencing. CONCLUSION ABO blood groups genotyping technology combined with serological typing can be used for accurate typing of ambiguous blood group, and better ensure the safety of blood transfusion.
ABO Blood-Group System/genetics* ; Alleles ; Blood Grouping and Crossmatching ; Exons ; Genotype ; Phenotype

OBJECTIVE: To identify the ABO positive and negative stereotypic inconsistencies in a dizygotic twin with positive stereotypic patterns and mixed agglutination, and explore the application of serological characteristics and gene sequence in congenital blood group chimeras. METHODS: ABO blood group identification, Rh and MN typing were performed using the microcolumn gel method and ABO genotyping was performed using the PCR-SSP method. RESULTS: In this patient, both anti-A and anti-B tubes had mixed hemagglutination of red blood cells, and the anti-ABO tube was AB type. The Rh typing of the patient was CcDEe. Mixed agglutination of red blood cells was observed in both anti-M and anti-N tubes in MN typing. The patient's father and mother was normal Type O and AB, respectively. There were three alleles in the ABO gene of the patient, O0101 came from his father, while A102 and B01 came from his mother. CONCLUSION The patient has two groups of red blood cells (type A and B). Because the patients is a dizygotic twin, these two groups of red blood cells can be chimeras formed by blood exchange between the twins. Through gene sequencing, it can be determined that the patient is a congenital A/B blood type chimera.
ABO Blood-Group System/genetics* ; Alleles ; Blood Grouping and Crossmatching ; Genotype ; Humans ; Polymerase Chain Reaction

OBJECTIVE: To investigate the effect of ABO gene α-1,3-D galactosyl transferase mutation on B antigen expression and its molecular mechanism. METHODS: The proband and their family members were identified by routine serological methods, and ABO genotyping and sequence analysis were performed by polymerase chain reaction-sequence specificity (PCR-SSP) and direct sequencing of PCR products from exon 1-7 of ABO gene. The 3D structural simulation of mutant proteins was performed by bioinformatics software. The effect of gene mutation on protein structural stability was analyzed. RESULTS: The proband and his family members were subtype B. ABO genotyping indicated that the proband's genotype was Bw12/O. Gene sequencing results confirmed the presence of ABO*BW.12 characteristic variation c.278C>T in the 6th exon of allele B, leading to the replacement of polypeptide chain p.Pro93Leu. The 3D structure simulation analysis of the protein showed that the hydrogen bonds and water molecules connected to the protein changed after amino acid substitution. The family investigation found that the grandfather, father, uncle and brother of the proband all carried the same ABO*BW.12 allele. CONCLUSION The mutation of the 6th exon c.278C>T of ABO gene led to the substitution of polypeptide chain amino acids, which affected the stability of α-1,3-D galactosyl transferase protein, resulting in the change of enzyme activity, and the Bw.12 phenotype, which can be stably inherited.
ABO Blood-Group System/genetics* ; Alleles ; Amino Acids/genetics* ; Animals ; Base Sequence ; Exons ; Genotype ; Male ; Mutant Proteins/genetics* ; Mutation ; Phenotype ; Water