A processed HLA-A*24:02 pseudogene found in the peripheral blood of a father and his son

We encountered a case that exhibited a discrepancy in human leukocyte antigen-A (HLA-A) type determined by sequence-based typing (SBT) and sequence-specific primer (SSP) molecular typing. The child of this case was identified as A* 02:01 homozygote and A* 02, A* 24, respectively. The HLA-A type of his father was A* 02:01, 26:01, but low-resolution SSP also showed unexpected amplification with A* 24 primers as with the child. Serologic typing of the child and the father was A2/blank and A2/A26, respectively. Sequencing analysis of the A* 24 variant in the child and the father showed a complete deletion of all introns of the A* 24:02 allele. Though rare, this type of processed pseudogene variant can be one of the causes of discrepancies between high- and low-resolution HLA typing.