Bugert P, Scharberg EA, Janetzko K, Rink G, Panter K, Richter E, Klüter H. A Novel Variant B Allele of the ABO Blood Group Gene Associated with Lack of B Antigen Expression.
ACTA ACUST UNITED AC 2008;
35:319-323. [PMID:
21512649 DOI:
10.1159/000141640]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Accepted: 01/30/2008] [Indexed: 11/19/2022]
Abstract
SUMMARY: BACKGROUND: The gene locus for the ABO blood group system encodes a glycosyltransferase. Alterations in the DNA sequence are associated with the blood groups and the expression levels of antigens on red blood cells. A number of ABO alleles have been described as the molecular basis of weak A or B antigens. PATIENTS AND METHODS: Here, we describe a novel variant B allele in a blood donor with discrepant results in routine forward (group A) and reverse (very weak anti-B isoagglutinins) ABO blood grouping. RESULTS: Determination of the ABO genotype using polymerase chain reaction-sequence-specific primers (PCR-SSP) indicated blood group A(2)B. Sequencing of the ABO gene exons 6 and 7 showed for 1 allele a G insertion into the GGGGGG sequence at position 811-816 of exon 7. The 816insG mutation (designated ABO*Bw20) led to a frame shift of the coding sequence and subsequent alteration of the protein sequence. The location of the mutation on a B allele was proven by PCR-SSP. Screening for the novel mutation in 211 blood donors with regular ABO phenotypes indicated that *Bw20 is a rare variant. CONCLUSIONS: The low levels of anti-B isoagglutinins associated with this novel variant indicate that residual undetectable amounts of B antigen may be present on red blood cells. The serological and molecular analysis of members of the blood donor's family further proved the phenotype-genotype correlation of the *Bw20 allele with antigen O and individually variable levels of anti-B isoagglutinins. The characterization of novel alleles associated with ABO subgroups may ensure the correct determination of blood groups in which serological methods are combined with molecular genetic approaches.
Collapse