HLA ‐ A locus allelic dropout in S anger sequence‐based typing due to the single nucleotide polymorphism of exon 1

Summary The DNA ‐based method is used widely for HLA genotyping in routine work, but some allele may be dropout in the genotyping procedure. Here, we reported a case with HLA ‐ A allele dropout in the S anger PCR ‐ SBT test. The initial PCR ‐ SBT method with a commercial agent kit was not characterized, and the result of L uminex technology indicated the dropout as a HLA ‐ A *02 allele. Subsequently, the sequences of exons 2–4 were fully matched with the A *02:07 and A *11:01:01 by allele group‐specific primer amplification PCR ‐ SBT . On further analysis, a novel allele A *02:07:07 was identified, which has one nucleotide difference from A *02:07:01 at position 6 C > G of exon 1. According to the sequencing for 5′‐ UTR to 3′‐ UTR , the novel single nucleotide polymorphism of exon 1 was contributed to HLA ‐ A locus allele dropout in the sample. Our results indicated multiplatform analysis is necessary when a conclusive HLA type cannot be determined by a single methodology.