Characterization of a novel O(1) variant allele at the ABO blood group locus.

We describe the identification and molecular characterization of a novel variant O(1) allele of the ABO blood group locus. The allele was found in a young child and by analyzing the maternal DNA we were able to show that a meiotic recombination event between the maternal O(1v-3) and B(1-1) alleles recreated a O(1)/B hybrid allele. Further characterization of intron 6 sequences delineated the putative recombination breakpoint between nucleotide position 42 and 163 of the intron. We propose that the novel O(1variant) allele should be named O(1v-7) and is a combination of exon 6 from a O(1v-3) allele and exon 7 from a B(1-1) allele.