UAS regulates expression of the cDNA of the spondyloarthritis-associated Hsap\HLA-B "* 27:05 " allele.
One of more than 60 very similar alleles of HLA-B that are categorized as HLA-B27 subtypes; these subtypes are designated as HLA-B*2701 to HLA-B*2763 (https://ghr.nlm.nih.gov/gene/HLA-B).