A novel blood group B subgroup: serological and genetic studies

• Published in: Transfusion medicine (Oxford, England) Vol. 14; no. 2; pp. 173 - 180
• Main Authors: Estalote, A. C., Palatnik, M., Chester, M. A., Olsson, M. L., Sant'Anna Gomes, B. M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK; Malden, USA Blackwell Science Ltd 01.04.2004
• Subjects: ABO blood group; ABO Blood-Group System - blood; ABO Blood-Group System - classification; ABO Blood-Group System - genetics; ABO gene; Adult; B antigen; Clinical Medicine; DNA Mutational Analysis; Family Health; Female; genetic polymorphism; Glycosyltransferases - genetics; Hematologi; Hematology; Heterozygote; Humans; Immune Sera; Infant, Newborn; Klinisk medicin; Male; Medical and Health Sciences; Medicin och hälsovetenskap; Mutation, Missense; Pedigree; Point Mutation; subgroup
• ISSN: 0958-7578; 1365-3148
• DOI: 10.1111/j.0958-7578.2004.00494.x

summary A discrepancy in the ABO blood groups between a newborn child and her parents was identified. Serological and DNA investigative techniques were performed. A weak variant of B (Bw) was detected on the erythrocytes of the child, her grandmother and great‐uncle. Adsorption–elution studies showed that their erythrocytes adsorb and yield anti‐B on elution. The Bw antigenic strength of the A1Bw cells of her mother and maternal aunt was reduced when compared to that of the A2Bw from another family member. Only one of 15 different anti‐B sera agglutinated the A1Bw erythrocytes. Agglutinin anti‐B that reacted strongly with normal B erythrocytes and did not agglutinate the Bw cells, was found in the sera of the A1Bw individuals. The Bw serum glycosyltransferase could not convert O cells into B cells and no B substance was found in saliva. All family members with the Bw/ABw phenotypes were heterozygous for a B allele and DNA sequencing revealed a novel missense mutation in exon 7 of the B allele (556A > G), resulting in M186V. This substitution changes a highly conserved region of the enzyme, proposed to be a disordered loop near the enzyme cleft, and is expected to diminish the enzyme's activity, leading to this Bw phenotype.