OBJECTIVE To explore the molecular mechanism for a blood sample with mixed-field hemagglutination upon determination of ABO blood group. METHODS Serological techniques were employed to identify the erythrocyte phenotype. The A and B antigens were detected by flow cytometry. The preliminary genotype of ABO gene was assayed with sequence-specific primer-polymerase chain reaction (PCR-SSP). Exons 6 and 7 of the ABO gene were amplified with PCR and analyzed by direct sequencing. Haplotypes of the ABO gene were analyzed by cloning sequencing as well. RESULTS The serological reaction pattern has supported an O phenotype when all the tubes were centrifuged for the first time. However, a mixed-field hemagglutination of red blood cells (RBCs) with anti-A antibodies was present after the tube was centrifuged five times later. A antigens were detected on the surface of partial red blood cells of the sample by flow cytometry. PCR- SSP results have shown that the preliminary ABO genotype was A/O. Analysis of the fragments of exons 6 and 7 of the ABO gene has indicated that heterozygosis lied as follows: 261G/A, 425T/T, 467C/T, 646A/T, 681A/G, 745C/T, 771C/T, 829A/G, conjecturing the genotype to be A307/O02, which was confirmed by haplotype sequence analysis. Compared with A101 allele, A307 allele has two missense mutations, 467C> T and 745C> T, which have resulted in substitutions Pro156Leu and Arg249Trp in the A glycosyltransferase polypeptide chain. CONCLUSION A variant allele (A307) has been identified for the first time in mainland China, which is responsible for the formation of A3 phenotype.
ABO Blood-Group System ; genetics ; Adult ; Genotype ; Humans ; Male ; Phenotype

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 analyze the different subtypes caused by c.721C>T substitution in the exon 7 of the ABO gene, and to investigate the related molecular mechanism of different antigens expression. METHODS: ABO subtypes in 7 samples were identified by standard serological methods. The exons 6, 7, and adjacent intron of ABO gene were amplified by Polymerase Chain Reaction (PCR), and the PCR products were analyzed by direct DNA sequencing and cloning sequencing. RESULTS: ABO subtypes phenotypes were A CONCLUSION c.721C>T substitution in the ABO gene causes p.Arg241Trp exchange resulting in the decreasing of GTA or GTB activities and weaker antigen expression. O.01.07 is a null allele which cannot form a functional catalytic enzyme has no effect on A
ABO Blood-Group System/genetics* ; Alleles ; Exons ; Genotype ; Mutation, Missense

OBJECTIVE: To determine the genotype of an individual suspected for Aw through DNA sequencing. METHODS: Serologic testing was carried out with standard methods. Exons 6 and 7 of the ABO genes were amplified by PCR and subjected to direct sequencing or sequenced after gene cloning. RESULTS: Serological testing showed that the forward typing and reverse typing were Aw and A, respectively. DNA sequencing revealed that the individual has carried an Aw allele and an O allele. Haplotype sequencing of each allele has revealed a nt543 variant (543G>C) in the Aw allele. CONCLUSION The individual was verified as a rare A subtype, which was previously unreported in mainland China.
ABO Blood-Group System/genetics* ; Alleles ; Exons ; Genotype ; Humans ; Phenotype

OBJECTIVE: To delineate the serological and molecular profiles of a patient with A(w)37B subtype. METHODS: The ABO bloodtypes of the proband, his wife and daughter were determined with a standard serological method. Their ABO genotypes were determined by sequence-specific primer polymerase chain reaction (PCR-SSP). All exons of the ABO gene were directly sequenced. Exons 6 and 7 of the ABO gene were further analyzed by cloning and sequencing. RESULTS: The red blood cells of the proband showed a weak B phenotype. His serum sample contained weak reactive anti-A antibody, which was defined as A(w)B blood group based on the serological characteristics. The A and B alleles were detected by blood group genotyping. Gene cloning and sequencing have identified a characteristic c.940A>G variant (ABO*AW.37) in exon 7 of the ABO gene, which resulted in substitution of Lysine by Glutamate at position 314. The proband's daughter has inherited the ABO*AW.37 allele. CONCLUSION The c.940A>G variant in exon 7 of the ABO gene probably underlay the decreased activity of GTA transferase and resulted in the Aw37 phenotype.
ABO Blood-Group System/genetics* ; Alleles ; Genotype ; Humans ; Pedigree ; Phenotype

OBJECTIVETo investigate the serological characteristics and the genetic status of the family of H-deficient blood group in Jining area of Shandong province in China.

METHODSABO, H, and Lewis blood groups in 3 probands were screened out by the serological method, and saliva testing was performed on all the individuals. The presence of weak A or B on the RBC was confirmed by using the adsorption-elution procedure.

RESULTSThree cases of H-deficient blood group were identified to be para-Bombay blood group (secretor), out of 3 cases, 2 cases were Bh, 1 case was Ah, and anti-H or anti-HI antibody was detected in their serum.

CONCLUSIONThree cases of H-deficerent blood group are para-Bombay phenotype, among them one proband's parents have been confirmed to be consanguineous relationship.

OBJECTIVE: To explore the serological characteristics and molecular biological mechanism of an a_el subtype specimen. METHODS: The ABO blood typing was identified by routine blood group serological and absorption/elution methods; PCR-SBT method for ABO genotyping: 7 exons of ABO gene were amplified by PCR, the amplified products were purified, and then sequencing primers were designed and the amplified products were sequenced directly for analysis; 3D molecular model was constructed and the difference of free energy (ΔΔG) was used to predict the GTA mutant stability. RESULTS: A antigen was not detected on erythrocytes through absorption and elution tests, which was not consistent with the serological characteristics of a_el, and the serological typing results were ambiguous. The ABO genotype was ABO*AEL.02/O.01.01, and there were two mutations in exon 7 of the gene, c.467C>T and c.646T>A, which could lead to the replacement of proline with leucine at position 156 (p.Pro156Leu) and phenylalanine with isoleucine at position 216 on the GTA, respectively. The 3D model predicts that the mutations do not introduce new hydrogen bonds to the GTA mutant and do not form a new secondary structure, but can lead to an increase in the ΔΔG value of the GTA mutant, suggesting a decrease in protein stability. CONCLUSION The serological characteristics alone is not reliable to determine the a_el subype; the a_el phenotype may be due to the GTA mutant that reduces enzyme stability.
ABO Blood-Group System/genetics* ; Alleles ; Genotype ; Isoleucine/genetics* ; Leucine/genetics* ; Phenotype ; Phenylalanine/genetics* ; Proline/genetics*

This study was aimed to investigate one case with rare type B(A) in ABO blood group by using serological and molecular biological methods, and analyze the cause of inconsistency resulting from multiple detections. The serological method was used to identify the serum type of ABO blood group, at the same time the PCR sequencing method was used to detect the genotypes. The results indicated that the group typing and reverse typing for the blood donor were inconsistent, the group typing was AB, the reverse typing was B. The ABO genotype was B(A) 04 /001. This genotype was involved in nt640A > G point mutation which caused valine replacing methionine at 214. It is concluded that the sample inconsistent between the group typing and reverse typing could be typed by molecular biological method, and the molecular basis of weak expression of ABO blood group is elucidated too.
ABO Blood-Group System ; genetics ; Blood Donors ; Blood Grouping and Crossmatching ; methods ; Genotype ; Humans ; Serologic Tests

OBJECTIVE: To delineate the blood group for a pair of twins with inconclusive ABO blood typing result. METHODS: Serological test for blood group was carried out by using ABO and Rh Blood Grouping Cards (Microcolumn Gel Immunoassay). Sequence specific primer-PCR (PCR-SSP), direct sequencing and TA clone sequencing were used to analyze the ABO gene. Genetic status was analyzed by using 16 short tandem repeat (STR) markers. RESULTS: Red blood cells of the twins displayed 2+ mixed agglutination phenomenon with anti-A, anti-A1 and anti-E. PCR-SSP and DNA sequencing of exons 6 to 7 revealed that they have an ABO*O.01.01/ABO*O.01.02 genotype. DNA sequencing of microsatellite enhancer region revealed presence of A gene. STR analysis revealed more than two haplotypes for 9 loci between the twins. After clustered by anti-A, the red blood cells were divided into two groups: A, CcDEe and O, CcDee, respectively. CONCLUSION Serological and molecular techniques have characterized the twins as blood group chimeras.
ABO Blood-Group System/genetics* ; Alleles ; Chimera/genetics* ; Genotype ; Humans ; Twins/genetics*

OBJECTIVE: To explore the molecular basis for an individual with Bw subtype. METHODS: Routine serological reactions were used to determine the surface antigens of erythrocytes and antibodies in serum. PCR-sequence-based typing (PCR-SBT) was used to analyze the coding regions of the ABO gene and erythroid-specific regulatory element in its intron 1. Amplicons for exons 5 to 7 containing the variant site were subjected to TA cloning for the isolation of the haploid and verification of the sequence. The 3D structure of mutant protein was predicted with Pymol software. Changes of amino acid residues and structural stability were also analyzed. RESULTS: Serological assay showed that the individual had weakened B antigen and anti-B antibody in his serum. His genotype was determined as ABO*B.01/ABO*O.01.01. Sequencing of the entire coding region of the ABO gene identified an additional heterozygous c.734C/T variant. No variant was found in the erythroid-specific regulatory element of intron 1. Haploid cloning and isolation has obtained an ABO*O.01.01 allele and a ABO*B.01 allele containing a c.734T variant, which has led to substitution of Thr by Ile at position 245 in the functional center of glycosyltransferase. Based on the 3D structure of the protein, the residues binding with the mutation were unchanged, but the bonding distance between the hydrogens was changed with the amino acid substitution. Meanwhile, the connections with water molecules were increased. CONCLUSION The c.734C>T variant of the GTB gene can lead to an amino acid substitution in the functional center of the enzyme, which in turn may affect the stability of glycosyltransferase B protein and reduceits enzymatic activity.
ABO Blood-Group System/genetics* ; Alleles ; Exons/genetics* ; Genotype ; Glycosyltransferases/genetics* ; Humans ; Male ; Phenotype