Molecular Characteristics of B Subgroups in Koreans / 대한진단검사의학회지

BACKGROUND: An accurate ABO blood type is essential for transfusion therapy. Genetic structures of ABO blood group and subgroup have been investigated and so far about 100 ABO alleles have been reported worldwide. This study was performed to investigate the molecular characteristics of B subgroups in the Korean population. METHODS: A total of 19 samples of B subgroups were collected from patients (n=11) and from blood donors (n=8) of Korean Red Cross blood centers; these samples had been typed serologically for the ABO blood group. Allele-specific polymerase chain reaction (PCR), direct sequencing of exon 6 and 7, and allele separation were performed for ABO gene analysis. RESULTS: The ABO PCR-RFLP genotyping results of 18 samples among the provisional 19 B subgroups were identical regardless of their phenotypes. Two new B alleles showing 255C>T base change and 547G>A base change were observed in B3 and A1B3 subgroups. CONCLUSIONS: Serologically unidentified B subgroups were unequivocally identified through molecular analyses of the ABO gene. And new ABO alleles observed only in the Korean B subgroups were recognized.

ABO gene analysis of cis-AB and B subgroup in blood donors / 대한수혈학회지

BACKGROUDS: Based on elucidation of genetic basis of ABO blood group, the genetic mutation of blood subgroup has been investigated. Especially, the discovery of base substitution such as C467T, G803C in cis-AB have made the efforts to determine cis-AB blood group by molecular method. This study was performed to investigate the ABO gene structure and usefulness of genotyping method in blood donors whose blood group are suspected as cis-AB and B subgroup. METHODS: Genotyping for ABO was performed in peripheral blood DNA samples from eight cis-AB donors and five B subgroup donors at red cross blood center. DNA sequencing was performed on Bint, B3 and two cis-AB samples. RESLUTS: All eight cis-AB donors showed that they have cis-AB allele and C467T substitution. Through DNA sequencing it was confirmed that cis-AB allele was derived from A allele mutation and two B subgroups showed no base sequence difference with B blood group. CONCLUSIONS: The genotyping method would be useful tool to determine blood group variants in blood donors. And more investigation is required for elucidation of genetic structure and gene expression of ABO blood subgroup.

Application of ABO genotyping in determination of ABO subgroups / 대한수혈학회지

BACKGROUND: The knowledge about the nucleotides sequence of 9th chromosome that regulates the phenotype of ABO blood group has made the ABO genotyping possible. Since the genotyping can be done with only a small amount of DNA sample, it was primarily applied to the field of forensic medicine. When applied to the blood bank, it is useful in the resolution for ABO discrepancies between the cell and serum typing and determination of A and B subgroups. Rapid ABO genotyping using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and its value in determination of ABO subgroups is presented. METHODS: ABO genotyping was performed in seven patients and three families, seven were the cases of ABO discrepancies in routine ABO grouping and three families were for the confirmation of the ABO group. To identify the 261th nucleotide, a 252 bp PCR amplifed fragment was amplified by PCR and digested with Kpn I. For 703th nucleotide, a 128 bp PCR amplified fragment was designed and digested with Alu I. To determine the ABO genotype, the patterns of digestion in DNA fragment were examined. RESULTS: Among the seven cases of ABO discrepancies, B3 and Ael were two cases each. Weakened B due to leukemia was the one, and the other two cases were cis-AB and Am. The three families for confirmation of the ABO group were acquired B due to infection one family, cis-AB two families. CONCLUSIONS: ABO genotyping is a rapid and reliable method that can be used in the case of ABO discrepancies and determination of ABO subgroups.

Identification of a novel Bx allele in a Chinese Han individual with B subgroup / 中国输血杂志

T missense mutation in exon 7. No novel point mutation at exons 6 and 7 of ABO gene was detected in the other four samples with B subgroup. Conclusion We define this allele as a novel B allele in Chinese Han individuals. The mutation of this novel allele in which the nucleotide changes from C to T at position 721 in exon 7, resulting in an amino acid change from Arg to Trp, results in the decrease of the enzyme activity. It indicates that the alteration of amino acid at position of 241 is critical to the activity of glycosyltransferases.