CLASSIFICATION OF MUTATIONS AT THE HLA-A LOCUS BY USE OF THE POLYMERASE CHAIN-REACTION

We investigated whether the polymerase chain reaction (PCR) could be u sed to determine the mechanism of mutation in lymphocyte clones mutate d at the HLA-A locus. Three polymorphisms, at Factor XIIIA, D6S109, an d intron 3 of the HLA-A gene, were used to study a series of clones pr eviously characterised by Southern blotting (SB) at multiple loci on c hromosome 6. For detection of loss of heterozygosity, the results of P CR and SB were concordant in 140 of 141 clones when polymorphism in th e Factor XIIIA region was studied and in 144 of 145 clones when polymo rphism in the HLA-A gene was studied. For classification of the mechan ism of mutation, PCR and SB gave the same result in 88 of 92 clones (9 6%) when a combination of the HLA-A and Factor XIIIA polymorphisms was used and in 46 of 47 clones (98%) when a combination of the HLA-A and D6S109 polymorphisms was used. The results indicate that PCR provides a simple and reliable method for categorising mutations at the HLA-A locus as arising from mitotic recombination, deletion, or from presump tive minor changes within the gene. Rare events such as gene conversio n, nondisjunction, or large deletions extending to the telomere will b e misclassified. However, such events are rare for mutations at this l ocus. (C) 1993 Wiley-Liss, Inc.