A Novel c.796 A>C Mutation in the ABO*B.01 Allele Responsible for CisAB Phenotype

Background: Individuals with the CisAB phenotype are rare in the Chinese population. In the present study, we investigated the sequence of the ABO gene and family members of a newborn suspected to have the CisAB phenotype. Methods: The ABO phenotype was detected using conventional serological tests. The full coding region of exons 1 to 7 of the ABO gene was amplified by polymerase chain reaction and was sequenced. The ABO haplotype was determined by the allele-specific primer sequencing method. Results: The proband and his father and grandfather were assigned the CisAB phenotype according to the results of the serological tests and family investigation. A novel CisAB allele was identified in the proband and his father and grandfather, which has only one nucleotide difference at position 796 from A to C (c.796A>C) compared with the ABO*B.01 allele. Conclusion: A novel CisAB (c.796A>C mutation in ABO*B.01) allele is the first identified in the Chinese population.