ABO*Ael03/O Genotype with ABO Discrepancy: The First Case in Korea

The Ael subgroup expresses the least amount of A antigens and could only be detected by performing the adsorption-elution test. The frequency of the Ael subgroup is about 0.001% in Koreans, and the Ael02 allele, which originates from A102, is the most frequently identified allele in the Korean population. We report a Korean family with the Ael03 allele identified by molecular genetic analysis. To the best of our knowledge, this is the first such report in Korea to date.

A Case of ABO*Ael02/O04 Genotype with Typical Phenotype O / 대한진단검사의학회지

Ael is a rare blood type which has the least amount of A antigen among A subgroups. It can be detected by special tests performed to resolve the discrepancy between red cell and serum typing in routine serological typing. The presence of A antigen on Ael red cell is demonstrable only by adsorption and elution tests. An Ael individual does not secret A substance in the saliva and may have anti-A antibody in the serum which is usually less reactive with the reagent red cells than anti-B antibody. In Korea, Ael02 has been reported more frequently than other Ael alleles. We report a case of Ael02/O04 who presented as typical phenotype O with strong anti-A and anti-B antibodies and no A antigen detected even by adsorption and elution tests. The case has been proved to be Ael02/O04 by direct sequencing analysis. In individuals with history of discrepancies in the results of ABO phenotyping, ABO genotyping is needed for an accurate evaluation of their blood type.

Molelular genetic analysis of Ael variant phenotype of ABO blood group system / 대한수혈학회지

BACKGROUND: Since the genes encoding glycosyltransferases synthesizing ABO antigens were cloned and sequenced in 1990, genetic polymorphisms and phenotype-genotype correlations have been reported by several investigators, but the genetic basis remains unclear for many subgroups. The Ael phenotype is one of the important A subgroups having very weak A antigen, and recent studies suggested that different alleles can result in this phenotype. METHODS: Three unrelated Ael subgroup samples from Korean blood donors were studied. Exons 6 and 7 of the ABO gene, 91% of the catalytic active part of the glycosyltransferase, were amplified and subjected to direct sequencing. RESULTS: Only C467T substitution in comparison with the consensus sequence of A gene was found in one Ael sample, but this mutation pattern was very commonly observed in normal A1 phenotype of Orientals. The other two samples had T646A (Phe216Ile) and G681A (silent) substitutions beside C467T substitution, reported first from a Japanese Ael individual. CONCLUSIONS: These results indicate that molecular genetic heterogeneity within the Ael subgroup was also seen.

A Case of Ael with Anti-A / 대한수혈학회지

We report a case of Ael in a 44-year old woman. The patient' red cells were typed as O and her serum had both anti-A and anti-B, but the agglutination strength with A1 cell was weaker (2+) than with B cell (4+) in her serum. Additional tests showed that the red cells were not agglutinated by anti-A,B and A antigen on patient' RBC was demonstrated by adsorption-elution test. Her saliva contained H but no A substance, and the ABO genotyping test identified her blood type as AO. We concluded that this was a case of blood type Ael with anti-A.

A Case of Ael with Anti-A

We report a case of Ael in a 44-year old woman. The patient s red cells were typed as 0 and her serum had both anti-A and anti-B, but the agglutination strength with Al cell was weaker (2+) than with B cell (4+) in her serum. Additional tests showed that the red cells were not agglutinated by anti-A,B and A antigen on patient s RBC was demonstrated by adsorption-elution test. Her saliva contained H but no A substance, and the ABO genotyping test identified her blood type as AO. We concluded that this was a case of blood type Ael with anti-A. (Korean J Blood Transfusion 10(1): 69 75, 1999)

Molecular genetic analysis of Ael subgroup of the ABO blood group system / 中国输血杂志

Objective To understand the molecular genetic basis of Ael subgroup of ABO blood group system in the Han nationality.Method 2 Ael individuals were defined by standard blood group serological techniques,and genomic DNA was prepared for PCR SSP genotyping.Primers were designed and synthesized to amplify complete exon 6 and 7 including flanking intron sequence,and direct sequencing of gel purified PCR amplified fragments was performed using Bigdye Sequencing kit.Result A possibility of regarding the Ael allele as A2,B,O1 and O2 genes had been eliminated by the PCR SSP assay.According to the sequence analysis,Ael gene had 2 mutations of which one was a nucleotide substitution at position 532 in intron 5 (C to T),and the other was a single nucleotide(G) insertion at position 798 to 804 in exon 7 which alter the 86 amino acids sequence of the glycosyltransferase and furthermore extend the translated proteins by 37 amino acids compared with A1 allele.Conclusion The mutations of (789 804)G insertion and C(I 5/532)T substitution is the molecular genetic basis for Ael phenotype.