Confirmation of the detection of HLA-A*0104N in a family: a PCR-SSP reaction for the allelic detection of HLA-A*0104N

The allele A*0104N has been detected in a family with a patient requiring a bone marrow transplant. The allele was found as a consequence of a discrep ant result when family members were typed using serology and polymerase cha in reaction using sequence-specific primers (PCR-SSP). Serological typing g ave an apparent HLA-A 'blank' while PCR-SSP revealed the presence of an A*0 1 allele in three family members who were serologically negative for A1. Se quencing-based typing (SBT) was then used to establish that the allele was A*0104N. A PCR-SSP reaction was subsequently designed and used for the alle lic detection of A*0104N. The study highlights the potential risks involved if molecular technology is used for typing, unless all non-expressed allel es are specifically detected.