A novel JK null allele associated with typing discrepancies among African Americans

The Jk_null(Jk-3) phenotype, attributable to null or silenced alleles, has predominantly been found in persons of Polynesian descent. With the increased use of molecular genotyping, many new silencing mutations have been identified in persons of other ethnic backgrounds. To date, only two JKnull alleles have been reported in African Americans, JK*01N.04and JK*01N.05.A comparative study was undertaken to determine whether JKmutations were present in the regional African American population. Results of donor genotyping were compared with previously recorded results of serologic tests, and discrepant results were investigated. Although the two previously identified polymorphisms were not detected in the discrepant samples, a novel allele (191G>A) was identified and was assigned the ISBT number JK*02N.09.This study illustrates a limitation of using single-nucleotide polymorphisms for prediction of blood group antigens. Immunohematology2013;29:145–148.