HLA-A, -B, -C, -DRB1 and -DQB1 allele and haplotype frequencies in Saudis using next generation sequencing technique.

Next generation sequencing (NGS) is a promising technique that can reveal the entire gene sequences and to the highest possible resolution without any phase ambiguities. We have used this technique to investigate the frequencies of HLA-A, -B, -C, -DRB1 and -DQB1 in a Saudi cohort of healthy individuals. We used NGS using the 454 genome sequence (GS) FLX System and Conexio assign atf 454 software to human leukocyte antigen (HLA) genotype eight class I and class II loci. A total of 158 healthy Saudi adults were analyzed. The most frequently observed allele for HLA-A was HLA-A*02:01:01:01 (13.6%); for HLA-B, HLA-B*50:01:01 (15.8%); for HLA-C, HLA-C*06:02:01:01 (18.7%); for HLA-DRB1, HLA-DRB1*07:01:01:01 (26.6%); and for HLA-DQB1, HLA-DQB1*02:01:01 (20.3%). The most common four loci haplotypes in the Saudi population were HLA-A*24:02:01:01-B*08:01:01-C*07:02:01:01-DRB1*03:01:01:01 and HLA-A*23:01:01-B*50:01:01-C*06:02:01:01-DRB1*07:01:01:01.. We have used a highly informative technique for HLA typing of a Saudi healthy cohort to establish allele and haplotype frequencies. These results should prove useful for population studies, disease associations and future planning of the unrelated bone marrow donor registry.

HLA class II polymorphism in Saudi patients with multiple sclerosis.

Several studies have investigated the association of different HLA antigens with multiple sclerosis (MS). However, only few studies have considered the association of high-resolution HLA type and MS with none yet from Saudi Arabia. The aim of this study was to investigate the association of HLA class II alleles with MS in the Saudi population. We used next-generation sequencing to investigate HLA association with MS. This study was conducted at King Abdulaziz Medical City in Riyadh, Saudi Arabia. We found that several HLA-DRB1 and DQB1 alleles were associated with MS. These alleles included HLA-DRB1*15:01 (odds ratio [OR]: 3.01; 95%, confidence interval [CI]: 1.68-5.54; P = .0001), HLA-DQB1*02:01 (OR: 1.76; 95% CI: 1.20-2.58; P = .0022), HLA-DQB1*06:02 (OR: 3.52; 95% CI: 1.87-6.86; P < .0001), and HLA-DQB1*06:03 (OR: 2.42; 95% CI: 1.16-5.25; P = 0.01). Interestingly, HLA-DRB1*15:01 was associated with increased risk of previous relapses. In addition, HLA-DRB1*15:01 and HLA-DQB1*06:02 were found to be associated with lower vitamin D levels. This study provides insights on the association of different HLA alleles with clinical characteristics and outcome of MS among Saudis. These insights can have future implications for the clinical management of MS based on the patient genetic profile.