A novel method for assigning TAP1 genotype using restriction enzyme plus PASA methodology

The function of the TAP gene products appears to be the transport of antigenic peptides into the lumen of the endoplasmic reticulum where peptides are loaded onto HLA molecules. The polymorphisms within the TAP genes and potential disease associations are the subject of intense current study. While several methods have been described for TAP1 genotyping, most of these methods are unable to definitively assign TAP1 genotypes to individuals heterozygous at more than one polymorphic position. A combination named TAP1U was observed in approximately 25% of study subjects. We developed a restriction enzyme based method that allows definitive TAP1 genotypes assignment to 100% of subjects. We also further developed and optimized TAP genotyping by PCR amplification of specific alleles (PASA) that resulted in significant time and cost savings. Hence, we report a novel method for assigning TAP genotypes for TAP1U subjects and the modified PASA reactions. These improvements facilitate the rapid and efficient assignment of TAP genotypes useful for large human disease-gene association studies.