الملخص الإنجليزي
Introduction: Variation in Human leukocytes antigen (HLA) alleles and haplotypes
distribution in a population are helpful for the analysis of the origin, migration, and degree
of admixture. It also provides data to study disease association and to match individuals
for solid organ and bone marrow transplantation. Current data on HLA alleles and
haplotype distribution in Oman are based on small sample size or missing some HLA loci.
To construct HLA haplotype for an individual, a family pedigree data and HLA typing are
needed which is time-consuming and costly. Using predictive models in haplotype
construction saves time and money, as a haplotype could be inferred from typing a few
HLA informative loci. Aim: The study aims to estimate HLA alleles and 5-loci haplotypes
distribution in the Omani population using a large sample size and validate maximum
likelihood estimation-expectation maximization (MLE-EM) algorithm for haplotype
construction. Method: We analyzed 2950 patients' samples with Omani nationality who
were HLA typed in HLA laboratory at SQUH between January 2015 and December 2019.
HLA haplotypes were constructed using MLE-EM predictive algorithm and compared
with haplotypes of 599 subjects of family study (gold standard method). Results: We
identified 20 HLA-A, 45 HLA-B, 15 HLA-C, 18 HLA-DRB1 and 7 HLA-DQ allele group
families. The most frequent allele groups in our population were HLA-A*02 (24.5%),
HLA-A*11 (11.3%), HLA-B*51 (17.3%), HLA- B*35 (14.7%), HLA-C*04 (18.3%),
HLA-C*07 (17.1%), HLA-DRB1*16 (35.6%), HLA-DRB1*03 (15.2%), HLA-DQ*05
(46.1%) and HLA-DQ*02 (26.6%). The most frequent five loci haplotype is HLA-A*02
-B*35- C*04 -DRB1*16-DQ*05 (3.243%). The agreement in our study for one haplotype
match was 73.7% and for both haplotypes, the match was 50.0%. Conclusion: This study
provides data about the HLA diversity, which can be very important in the process of
unrelated donor search, and in addition yields control group for future disease association
studies in the Omani population.
