Genotype Analysis of the JR Blood Group in an East Asian Population Using Tetra-Primer ARMS-PCR

The JR blood group system, officially designated ISBT JR 032, consists of a single antigen called Jr^a. This is a high frequency antigen in most populations. The Jr(a-) phenotype is more prevalent in Japanese and Asian populations. Individuals with the Jr(a-) blood type can be recognized incidentally by the production of anti-Jr(a) antibodies and verified by the existence of two null ABCG2 alleles.

We used direct sequencing to analyze the genotype frequency of the ABCG2 null allele (c.376C>T, rs72552713) and compared it with East Asian genomic databases. We developed tetra-primer amplification refractory mutation system-polymerase chain reaction (ARMS-PCR), which is a simple, precise method for determining an individual's genotype and suitable for clinical use, and analyzed a cohort of 300 healthy Koreans.

Using direct sequencing, we found that 14 individuals in the cohort carried a heterozygous ABCG2 null allele. We optimized the ARMS-PCR technique to detect and identify this null allele precisely. We identified the presence of this null allele in a heterozygous state using ARMS-PCR.

The minor allele frequency of the ABCG2 null allele in the Korean cohort was 2.3%. The estimated genotype frequencies of homozygotes and heterozygotes for this null allele are 0.05% and 4.56%, respectively. The newly developed ARMS-PCR assay would be useful for determining the Jr(a-) antigen status in patients who produce anti-Jr(a) antibodies as well as for selecting Jr(a-) blood donors.