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A novel cis‐AB allele derived from a unique 796C>A mutation in exon 7 of ABO gene
Author(s) -
Tzeng ChengHwai,
Chen YingJu,
Lyou JauYi,
Chen PeiShan,
Liu HsuengMei,
Hu HuiYu,
Lin JeongShi,
Yu LungChih
Publication year - 2005
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/j.1537-2995.2005.04108.x
Subject(s) - nonsynonymous substitution , allele , genetics , exon , biology , phenotype , genotype , gene , allele frequency , abo blood group system , mutation , microbiology and biotechnology , genome
BACKGROUND: The cis ‐AB phenotype is very rare, and only three genotypes that correspond to specific ABO allele changes have been reported. Cis‐AB01 involves the A102 allele with a nonsynonymous substitution G803C in exon 7 , whereas cis‐AB02 and cis‐AB03 involve different nonsynonymous substitutions A796C and C700T, respectively, on the B101 allele background. The nucleotide substitutions give rise to a change of the respective glycosyltransferase, resulting in varying bifunctional AB transferase activities. STUDY DESIGN AND METHODS: Two cis ‐AB phenotypes were identified in a Taiwanese C. family and two unrelated individuals, respectively. Serologic studies, molecular cloning, and sequencing of exon 6 and exon 7 were carried out to determine their respective phenotypic characteristics and cis‐AB alleles. A cohort of 300 AB‐phenotype, healthy random individuals served as controls. RESULTS: A novel cis‐AB allele is uncovered out of the three family members, of which a 796C>A substitution occurs predicting an amino acid change at residue 266 of leucine to methionine on the background of A102 allele. It is serologically like cis‐AB03 , an A 2 B phenotype, but molecularly different. Both of the two unrelated individuals are of cis‐AB01 allele, and all of the 300 AB blood group controls are excluded cis ‐AB phenotype. CONCLUSION: The C. family described carries a novel cis‐AB allele that differs molecularly from all previously reported cis‐AB alleles.