HLA-A, -B and -DRB1 allele frequencies in Cyrenaica population (Libya) and genetic relationships with other populations.

The frequencies of HLA-A, HLA-B and HLA-DRB1 alleles in 118 unrelated Libyans from Benghazi (Cyrenaica) were analysed using high resolution typing and compared with other populations. Their relatedness has been tested by correspondence analyses and principal component analysis. The most frequent HLA-A alleles were A(*)02:01:01:01 (15.7%), A(*)01:01:01:01 (11.4%) and A(*)03:01:01:01 (9.3%). For the HLA-B locus, the commonest allele was HLA-B(*)50:01:01 (14.4%) followed by B(*)51:01:01 (9.8%) and B(*)08:01:01 (6.4%). For the HLA-DRB1 locus, the commonest was HLA-DRB1(*)07:01:01:01 (16.9%) followed by DRB1(*)03:01:01:01 (13.6%) and DRB1(*)13:02:01 (9.3%). The most frequent two-locus haplotypes were HLA-A(*)02:01:01:01-B(*)07:02:01 (3.0%) and HLA-B(*)50:01:01-DRB1(*)07:01:01:01 (9.6%), and three-locus haplotypes were HLA-A(*)02:01:01:01-B(*)50:01:01-DRB1(*)07:01:01:01 (4.2%) and HLA-A(*)11:01:01-B(*)52:01:01:01-DRB1(*)15:02:01 (2.5%). This study is the first on the HLA status of a Libyan population. The results, when compared to similar HLA data obtained previously from African and Mediterranean populations, indicate genetic influences from several ethnic groups. Moreover, the differences in the HLA allele frequencies between the Libyan population and others reveals that significant admixture has occurred between the original Berber inhabitants and neighbouring and more distant populations, even though a strong genetic Berber substratum remains. These data will be of value to future anthropological and disease association studies involving the Libyan population.