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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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The HLA-B50 serologic family is very frequent in people of Arabic origin. In Saudi Arabia, HLA- B50 is the most frequent HLA- B allele. The aim of this study was to investigate the distribution of HLA- B50 alleles in healthy Saudi individuals. A total of 162 healthy Saudi individuals were selected based on low-resolution HLA typing. DNA samples were typed by sequence-based typing method for exons 2, 3 and 4 of the HLA- B locus (Genome Diagnostics B.V.). The HLA- B*50 alleles were analysed using SBT engine software. HLA-B*50:01:01 was found in 161 of 162 individuals (99.4%), while HLA- B*50:09 was found in one individual (0.6%). HLA-B*50:01:01 is the most common HLA- B50 allele in Saudi Arabia. [ABSTRACT FROM AUTHOR]

Three new HLA-C alleles were identified by sequence-based typing method ( SBT) in donors for the Saudi Bone Marrow Donor Registry ( SBMDR). HLA-C*14:02:13 differs from HLA-C*14:02:01 by a silent G to A substitution at nucleotide position 400 in exon 2, where lysine at position 66 remains unchanged. HLA-C*15:72 differs from HLA-C*15:22 by a nonsynonymous C to A substitution at nucleotide position 796 in exon 3, resulting in an amino acid change from phenylalanine to leucine at position 116. HLA-C*15:74 differs from HLA-C*15:08 by a nonsynonymous C to T substitution at nucleotide position 914 in exon 3, resulting in an amino acid change from arginine to tryptophan at position 156. [ABSTRACT FROM AUTHOR]

In this report, we present two novel HLA-A alleles: HLA-A*02:433 and HLA-A*02:434. These alleles were identified by sequence-based typing method ( SBT), in two donors for the Saudi Bone Marrow Donor Registry ( SBMDR). Allele A*02:433 is identical to A*02:05:01G except for a G to A substitution at nucleotide position 449 in exon 2. This substitution results in glycine to serine substitution at position 83. Whereas, allele A*02:434 is identical to A*02:01:01G except for a C to A substitution at nucleotide position 245 in exon 2, which results in phenylalanine to threonine substitution at position 15. The generation of both alleles appears to be the result of nucleotide point mutation involving 02:01:01 and 02:05:01. [ABSTRACT FROM AUTHOR]