title: HLA genotypes and variant alleles in Sudanese families of Arab-Negroid tribal origin.
abstract: The indigenous population of the Blue Nile Province, Sudan, is an Arab-Negroid admixture, although some isolates of west African origin (Fallata) have begun to intermix with the indigenous population. Consanguineous marriages are common in these Muslim families. Members of 22 nuclear families were typed for HLA class I and II antigens using complement-dependent microcytotoxicity with Ninth International Workshop (9th WS) and local reagents. Considerable polymorphism was observed at each locus with a majority of the World Health Organization (WHO)-recognized alleles represented in the parental sample, albeit at low frequency. Seven parental haplotypes carried A locus alleles which were not identical to WHO-recognized specificities. All appeared to be Aw19-related specificities. Five B locus serologic variants were observed; all appeared distinct from WHO-recognized specificities. In one family we observed a new DR-DQ association; DR4 segregated with DQw2, rather than with DQw3. As has been observed for several other genetic systems in these tribes, considerable polymorphism was found for all class I and class II gene products in spite of a high level of consanguinity. Tribal admixture and/or a selective advantage in protecting the population against disease may account for this unexpectedly high level of heterozygosity.
authors.affiliation: Department of Microbiology and Immunology, Duke University Medical Center, Durham, North Carolina 27710.
authors.forename: F E
authors.initials: FE
authors.lastname: Ward
authors.forename: J B
authors.initials: JB
authors.lastname: Jensen
authors.forename: N H
authors.initials: NH
authors.lastname: Abdul Hadi
authors.forename: A
authors.initials: A
authors.lastname: Stewart
authors.forename: J V
authors.initials: JV
authors.lastname: Vande Waa
authors.forename: R A
authors.initials: RA
authors.lastname: Bayoumi
mesh_terms: D044383:Black People / Q000235:genetics; D003241:Consanguinity; D003601:Cytotoxicity Tests, Immunologic; D005260:Female; D005838:Genotype; D015395:Histocompatibility Antigens Class I / Q000097:blood / Q000235:genetics / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000097:blood / Q000235:genetics / Q000276:immunology*; D006650:Histocompatibility Testing; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D013397:Sudan / Q000208:ethnology
chemical_list: D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II