The Distribution of HLA‐DRB4 Alleles Among HLA‐DRB1*07:01‐Positive Haplotypes in Saudi Arabia

This study investigates the distribution of human leukocyte antigen (HLA)-DRB4 alleles in HLA-DRB1*07:01-positive haplotypes within a Saudi cohort of 313 individuals. It identifies strong linkage disequilibrium between HLA-DRB1*07:01 and specific alleles. The most prevalent HLA-DRB1∼DQB1 combination identified is DRB1*07:01∼DQB1*02:02. Additionally, for the HLA-DRB1*07:01∼DQB1*03:03 association, DRB4*01:01 was found to be more common than the DRB4*01:03N allele. The most frequently observed extended haplotype is HLA-A*02:01∼C*06:02∼B*50:01∼DRB1*07:01∼DRB4*01:03∼DQA1*02:01∼DQB1*02:02∼DPA1*01:03∼DPB1*04:01. These findings emphasize the distinct genetic characteristics of the Saudi population and contribute to understanding haplotypic diversity, particularly the prevalence of HLA-DR7-related alleles and their implications for disease susceptibility and transplantation compatibility.