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About the Authors:
Fasil Tekola Ayele
* E-mail: [email protected]
Affiliation: Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
Elena Hailu
Affiliation: Armauer Hansen Research Institute, Addis Ababa, Ethiopia
Chris Finan
Affiliation: Brighton and Sussex Medical School, Brighton, United Kingdom
Abraham Aseffa
Affiliation: Armauer Hansen Research Institute, Addis Ababa, Ethiopia
Gail Davey
Affiliation: Brighton and Sussex Medical School, Brighton, United Kingdom
Melanie J. Newport
Affiliation: Brighton and Sussex Medical School, Brighton, United Kingdom
Charles N. Rotimi
Affiliation: Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
Adebowale Adeyemo
Affiliation: Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
Introduction
The human leukocyte antigen (HLA) locus, located on chromosome 6p21.3, is the most polymorphic and gene-dense region of the human genome [1]. HLA genes play important roles in the immune system and have multiple alleles that show extensive variation across human populations. The HLA locus has been a focus for genomic research and clinical practice for several reasons: (i) it is associated with susceptibility to or resistance against several infectious, autoimmune and inflammatory diseases; (ii) it is very informative in studies of human genetic diversity; and, (iii) it is central to donor-recipient matching in tissue and organ transplantation [2]. Understanding the HLA system in African populations has unique advantages. Africa is the most genetically diverse geographical region in the world and consequently, it harbours diverse and novel HLA alleles such as the class II DQA1*0403N [3], DPA1*010602 [4], DPB1*9401, DPB1*9501 [5], DPA1*010303, and DPA1*0303 [6] alleles. HLA alleles are found to be associated with susceptibility and resistance to infectious diseases including HIV/AIDS, tuberculosis, and malaria that impose huge public health burdens in Africa [7], [8]. HLA studies have also yielded important insights into the role of pathogens in driving HLA polymorphism. For example, a study that analyzed 61 human populations across the world showed that populations that have a greater burden of pathogens show higher HLA diversity and that populations farther from Africa (geographic distance measured through landmasses from Ethiopia) are characterized by lower...