Identification of a novel HLA DRB1 exon 2 sequence, DRB1*1345

Five different haplotypes in the human HLA D region are recognized based on their gene composition. The HLA DR52 associated DRB1 alleles include DRB1*03/08/11/12/13/14 and are characterized by the YST sequence motif in the codons 10-12 but vary in other polymorphic regions. The mechanisms generating the extensive variability are not entirely clear. Some alleles have probably arisen from point mutations, but most polymorphism has probably been caused by intralocus gene conversion, and the distinction between the ancient serologically defined groups is more and more difficult. This report describes the identification of a novel DRB1* allele - DRB1*1345 - found in a kidney transplant recipient from East Africa. The new allele shows the closest resemblance to DRB1*1114 and DRB1*1323. It differs from both those alleles at codons 57, 58 and 60, where the new allele carries the 'A-H' sequence motif common to DRB1*14 alleles such as 1401/04/07/10/16/25. This motif is only found in one other DRB1*13 allele namely DRB1*1343.