A Case of a Family with a High Frequency of cis-AB / 대한수혈학회지

ABSTRACT

The cis-AB phenotype is relatively common in the Japanese and Korean populations. Phenotypes of cis-AB include variables such as A2B3, A2B and A1B3. A few cases of cis-AB with phenotype A1 have been reported. Recently, we experienced a case with one family member identified with phenotype A1, genotype cis-AB/A and a high frequency of cis-AB. A 34-year-old woman visited the hospital for prenatal testing. The ABO phenotype of the patient was A2B3. To confirm the presence of cis-AB, ABO typing and genotyping of the patient's family were performed. The patient's mother and father were typed as normal group O and A, respectively. The ABO genotype of the mother was identified as cis-AB/A. The four sisters and brothers were typed as cis-AB. The normal incidence of cis-AB in a family is 50%. Interestingly, ABO typing revealed that all five members of the family had cis-AB in this case.