Novel JK*01 allele with c.299C>T p.(Thr100Ile) single nucleotide variant associated with loss of Jka expression in two African American donors

The JK blood group system encodes the antithetical antigens Jk^a and Jkb as well as Jk3.1 SLC14A1 on chromosome 18 spans approximately 28 kb and has 10 exons. The diallelic single nucleotide variant (SNV) c.838G>A p.(Asp280Asn) gives rise to the antithetical antigens Jk^a or Jkb, respectively. At the time of this publication and including this novel allele, there are 12 JK*01 alleles encoding Jk(a+w) and 29 JK*01 null alleles, and 6 JK*02 alleles encoding Jk(b+w) and 30 JK*02 null alleles.²

We describe two African American donors whose red blood cells (RBCs) tested Jk(a–b+) with polyclonal and monoclonal antisera. The RBC genotyping panel HemoID DQS (Agena Bioscience, San Diego, CA) predicted the sample to type Jk(a+b+). This discrepancy was investigated using Sanger sequencing of the coding exons and exon/intron junctions of SLC14A1.