A simple and rapid method for HLA‐DQA1 genotyping by digestion of PCR‐amplified DNA with allele specific restriction endonucleases

The second exon of the HLA‐DQA1 genes was selectively amplified from genomic DNAs of 72 HLA‐homozygous B cell lines by the polymerase chain reaction (PCR). Amplified DNAs were digested with HaeIII, Ddel, ScrFI, FokI and RsaI, which recognize allelic sequence variations in the polymorphic segments of the DQA1 second exon, and then subjected to electrophoresis in polyacrylamide gels. Eight different polymorphic patterns of restriction fragments were obtained, and seven were identical to patterns predicted from the known DNA sequences, correlating with each HLA‐DQw type defined by serological typing. The remaining one pattern cannot be explained from the sequence data, suggesting the presence of a novel DQA1 allele at the nucleotide level. This PCR‐RFLP method provides a simple and rapid technique for accurate definition of the HLA‐DQ types at the nucleotide level, eliminating the need for radioisotope as well as allele specific oligonucleotide probes and can be extended and applied to HLA‐DR, ‐Dw DP typing.