HLA Class I and Class II Alleles and Haplotypes Confirm the Berber Origin of the Present Day Tunisian Population

Contribution of HLA class I (A, B, C) and HLA class II (DRB1, DQA1, DQB1) alleles and haplotypes in exploring ethnic origin of central Tunisians

BACKGROUND

Estimation of HLA (Human leukocyte Antigen) alleles' frequencies in populations is essential to explore their ethnic origin. Anthropologic studies of central Tunisian population were rarely reported. Then, in this work, we aimed to explore the origin of central Tunisian population using HLA alleles and haplotypes frequencies.

METHODS

HLA class I (A, B, C) and HLA class II (DRB1, DQA1, DQB1) loci genotyping of 272 healthy unrelated organ donors was performed by Polymerase Chain Reaction-Sequence Specific Oligonucleotide (PCR-SSO). We compared central Tunisians with other populations (Arabs, Berbers, Mediterraneans, Europeans, Africans, etc.) using alleles and haplotypes frequencies, genetic distances, Neighbour-Joining dendrogram and correspondence analysis.

RESULTS

Among the 19 HLA A alleles, the 26 HLA B alleles, the 13 HLA C alleles, the 15 HLA DRB1 alleles, the 6 HLA DQA1 alleles and the 5 HLA DQB1 alleles identified in the studied population, HLA A*02 (22.8%), HLA B*50 (13.1%), HLA C*06 (21.8%), HLA DRB1*07 (17.8%), HLA DQA1*01 (32.1%) and HLA DQB1*03 (31.6%) were the most frequent alleles. The extended haplotypes HLA A*02-B*50-C*06-DRB1*07-DQA1*02-DQB1*02 (1.97%) was the most frequent HLA six-loci haplotype.

CONCLUSION

Central Tunisians were very close to other Tunisian populations, to Iberians and North Africans. They were rather distant from sub-Saharan populations and eastern Mediterraneans especially Arabs although the strong cultural and religious impact of Arabs in this population.

HLA allele and haplotype frequencies in Kazakhstani Russians and their relationship with other populations

HLA class I and class II genotypes from 947 Kazakhstani individuals of Russian origin were analyzed for investigating their most likely origin. The results were compared with similar data from other Russians (East and West), and also Worldwide populations, using standard genetic distances, neighbor-joining dendrograms, correspondence and haplotype analysis. Of the five HLA loci analyzed (HLA-A, HLA-C, HLA-B, HLA-DRB1, and HLA-DQB1) genotyped, 216 HLA alleles were identified. The most frequent alleles were A*02:01 (26.5%), B*07:02 (11.1%), C*04:01 (13.5%) and C*06:02 (12.1%), DRB1*07:01 (13.8%) and DRB1*15:01 (12.2%), and DQB1*03:01 (19.7%). Significant linkage disequilibrium was noted between all HLA pairs. DRB1*15:01 ~ DQB1*06:02 (10.5%), B*07:02 ~ C*07:02 (10.0%), B*07:02 ~ DRB1*15:01 (6.3%), and A*01:01 ~ B*08:01 (4.5%) were the most frequent two-locus haplotypes identified. Subsequent analyses showed that Kazakhstani Russians were closely related to West Russia-residing populations (Northwest Slavic, Vologda, Chelyabinsk, Moscow), East Europeans (Belarus Brest, Ukraine, Poland) and Scandinavians (Swedish, Finns), but distinct from East Russia-residing populations (Tuvians, Siberians from Chukotka, Kamchatka, and Ulchi) and East Mediterraneans (Levantines, Turks, North Macedonians, Albanians), and East Asians (Koreans, Japanese, Taiwanese, Mongolians). These results are in accordance with historical data indicating that the Russians of central Asia originate mainly from European Russia during the migratory flow of 18th and 19th centuries.

HLA pharmacogenetic markers of drug hypersensitivity from the perspective of the populations of the Greater Middle East

Specific HLA associations with drug hypersensitivity may vary between geographic regions and ethnic groups. There are little to no data related to HLA-drug hypersensitivity on populations who reside in the Greater Middle East (GME), a vast region spanning from Morocco in the west to Pakistan in the east. In this review, the authors intended to summarize the significant HLA alleles associated with hypersensitive drug reactions induced by different drugs, as have been found in different populations, and to summarize the prevalence of these alleles in the specific and diverse populations of the GME. For example, HLA-B*57:01 allele prevalence, associated with abacavir-induced hypersensitivity, ranges from 1% to 3%, and HLA-DPB1*03:01 prevalence, associated with aspirin-induced asthma, ranges from 10% to 14% in the GME population. Studying pharmacogenomic associations in the ethnic groups of the GME may allow the discovery of new associations, confirm ones found with a low evidence rate and enable cost-effectiveness analysis of allele screening before drug use.

Distribution of HLA-B Alleles and Haplotypes in Qatari: Recommendation for Establishing Pharmacogenomic Markers Screening for Drug Hypersensitivity

Human leukocyte antigen (HLA) proteins are present at the cellular surface of antigen-presenting cells and play a crucial role in the adaptive immune response. Class I genes, specifically certain HLA-B alleles, are associated with adverse drug reactions (ADRs) and are used as pharmacogenetic markers. Although ADRs are a common causes of hospitalization and mortality, the data on the prevalence of HLA-B pharmacogenetics markers in Arab countries are scarce. In this study, we investigated the frequencies of major HLA-B pharmacogenomics markers in the Qatari population. Next-generation sequencing data from 1,098 Qatari individuals were employed for HLA-B typing using HLA-HD version 1.4.0 and IPD-IMGT/HLA database. In addition, HLA-B pharmacogenetics markers were obtained from the HLA Adverse Drug Reaction Database. In total, 469 major HLA-B pharmacogenetic markers were identified, with HLA-B*51:01 being the most frequent pharmacogenetic marker (26.67%) in the Qatari population. Moreover, HLA-B*51:01 is associated with phenytoin- and clindamycin-induced ADRs. The second most frequent pharmacogenetic marker was the HLA-B*58:01 allele (6.56%), which is associated with allopurinol-induced ADRs. The third most frequent pharmacogenetic marker was the HLA-B*44:03 allele, which is associated with phenytoin-induced ADRs. The establishment of a pharmacogenetics screening program in Qatar for cost effective interventions aimed at preventing drug-induced hypersensitivity can be aided by the highly prevalent HLA-B pharmacogenetic markers detected here.

HLA-A, -B, -C, -DRB1 and -DQB1 allele and haplotype frequencies in Lebanese and their relatedness to neighboring and distant populations

BACKGROUND

This study examined the origin of present-day Lebanese using high-resolution HLA class I and class II allele and haplotype distributions. The study subjects comprised 152 unrelated individuals, and their HLA class I and class II alleles and two-locus and five-locus haplotypes were compared with those of neighboring and distant communities using genetic distances, neighbor-joining dendrograms, correspondence, and haplotype analyses. HLA class I (A, B, C) and class II (DRB1, DQB1) were genotyped at a high-resolution level by PCR-SSP.

RESULTS

In total, 76 alleles across the five HLA loci were detected: A*03:01 (17.1%), A*24:02 (16.5%), B*35:01 (25.7%), C*04:01 (25.3%), and C*07:01 (20.7%) were the most frequent class I alleles, while DRB1*11:01 (34.2%) and DQB1*03:01 (43.8%) were the most frequent class II alleles. All pairs of HLA loci were in significant linkage disequilibrium. The most frequent two-locus haplotypes recorded were DRB1*11:01 ~ DQB1*03:01 (30.9%), B*35:01-C*04:01 (20.7%), B*35:01 ~ DRB1*11:01 (13.8%), and A*24:02 ~ B*35:01 (10.3%). Lebanese appear to be closely related to East Mediterranean communities such as Levantines (Palestinians, Syrians, and Jordanians), Turks, Macedonians, and Albanians. However, Lebanese appear to be distinct from North African, Iberian, and Sub-Saharan communities.

CONCLUSIONS

Collectively, this indicates a limited genetic contribution of Arabic-speaking populations (from North Africa or the Arabian Peninsula) and Sub-Saharan communities to the present-day Lebanese gene pool. This confirms the notion that Lebanese population are of mixed East Mediterranean and Asian origin, with a marked European component.

Spectrum of Genetic Diseases in Tunisia: Current Situation and Main Milestones Achieved

Genetic diseases in Tunisia are a real public health problem given their chronicity and the lack of knowledge concerning their prevalence and etiology, and the high rates of consanguinity. Hence, we performed systematic reviews of the literature in order to provide a more recent spectrum of these disorders and to expose the challenges that still exist to tackle these kinds of diseases. A manual textual data mining was conducted using MeSH and PubMed databases. Collected data were classified according to the CIM-10 classification and the transmission mode. The spectrum of these diseases is estimated to be 589 entities. This suggests remarkable progress through the development of biomedical health research activities and building capacities. Sixty percent of the reported disorders are autosomal recessive, which could be explained by the high prevalence of endogamous mating. Congenital malformations (29.54%) are the major disease group, followed by metabolic diseases (22%). Sixty percent of the genetic diseases have a known molecular etiology. We also reported additional cases of comorbidity that seem to be a common phenomenon in our population. We also noticed that epidemiological data are scarce. Newborn and carrier screening was only limited to pilot projects for a few genetic diseases. Collected data are being integrated into a database under construction that will be a valuable decision-making tool. This study provides the current situation of genetic diseases in Tunisia and highlights their particularities. Early detection of the disease is important to initiate critical intervention and to reduce morbidity and mortality.

Origin of the Ukrainian minority of Kazakhstan as inferred from HLA-A, -B, -C, -DRB1, and -DQB1 alleles and haplotypes distribution

The present-day population of Kazakhstan comprises more than a hundred ethnic and linguistic groups, of which Ukrainians rates numerically as the fourth, following native Kazakhs, Russians, and Uzbeks. We investigated the HLA profile of Kazakhstani Ukrainians and compared them with those of other populations by applying genetic distances, correspondence analysis, admixture, and haplotype examination. Of the 128 HLA alleles identified, A*02:01 (28.64%), B*07:02 (9.71%), B*13:02 (9.71%), C*06:02 (15.05%), DRB1*07:01 (15.20%), and DQB1*03:01 (24.76%) were the utmost common alleles. The most common 2-locus haplotypes identified were A*02:01 ~ B*13:02 (6.66%), B*13:02 ~ DRB1*07:01 (6.57%), B*13:02 ~ C*06:02 (10.10%), and DRB1*01:01 ~ DQB1*05:01 (12.12%), while A*02:01 ~ B*13:02 ~ C*06:02 ~ DRB1*07:01 ~ DQB1*02:01 were the most frequent five-locus haplotype (4.04%) in Kazakhstani Ukrainians. Comparative analysis revealed that Ukrainians of Kazakhstan are closely related to Eastern Europeans (included Ukrainians), and European Russians, but distant from Asian populations. This supports the historical notion that Kazakhstani Ukrainians originated from Ukraine, following their massive migrations to central Asia in the 18th-20th centuries. This article is protected by copyright. All rights reserved.

HLA-A, -B, -C, -DRB1 and -DQB1 allele and haplotype frequencies and phylogenetic analysis of Bahraini population

The origin of Arab-speaking population is classified according to their geographical location, ethnic background, and historical influx of nearby and distant populations. Data on HLA class I and class II loci in (Arabian Peninsula) Bahraini population are lacking. We analyzed HLA genetic profile of Bahrainis with neighboring communities, and with Levantines, North Africans, Sub-Saharans, Europeans, and Asians, using genetic distances, neighbor-joining dendrograms, correspondence and haplotype analysis. HLA class I and class II genotyping were done by high resolution PCR-SSP in 175 Bahraini subjects. In total, 19 HLA-A, 33 HLA-B, 15 HLA-C, 14 DRB1 and 7 DQB1 alleles were identified. The most common class I alleles were A*02:01:01 (18.3%), A*01:01:01(15.4%), B*35:01:02 (12.9%), C*12:01:01 (15.1%), and C*04:01:01 (14.9%), while DRB1*03:01:01 (18.0%), DQB1*02:01:01 (29.1%), and DQB1*05:01:01 (24.9%) were the most frequent class II alleles. Significant linkage disequilibrium was seen between all HLA loci pairs. DRB1*03:01:01-DQB1*02:01:01 (15.18%) was the most frequent two-locus haplotype. Significant negative Fnd values were observed, indicating balancing selection at studied loci. Bahrainis appear to be related to Western Mediterranean (North Africans, Iberians and French), but relatively distinct from Levantines (Palestinians, Lebanese, and Jordanians) and Sub-Saharans. This indicates limited genetic contribution of Levantine Arabs and Sub-Saharans to the Bahraini gene pool.

HLA Haplotype Frequencies and Genetic Profiles of the Kuwaiti Population

OBJECTIVE

The aim of this study was to assess the HLA haplotype frequencies and genetic profiles of the Kuwaiti population.

MATERIALS AND METHODS

Whole venous blood was obtained from 595 healthy, unrelated Kuwaiti volunteers. The study population was genotyped for HLA class I (HLA-A, HLA-B, and HLA-C) and class II (HLA-DRB1 and HLA-DQB1) loci using sequence-specific oligonucleotide (SSO) probe-based hybridization and high-resolution HLA genotyping. Haplotype frequencies were estimated using an implementation of the expectation maximization algorithm that resolves both phase and allelic ambiguity. The Kuwaiti population was compared with other populations from the US National Marrow Donor Program (NMDP), by running a principal component analysis (PCA) on the relevant haplotype frequencies.

RESULTS

The most common HLA class I alleles in Kuwait were HLA-A*02:01g, HLA-C*06:02g, and HLA-B*50:01g with frequencies of 16, 14, and 12%, respectively. The most common HLA class II alleles in Kuwait were HLA-DQB1*02:01g and HLA-DRB1*07:01 with frequencies of 29.7 and 16.5%, respectively. The most common Kuwaiti haplotype observed was HLA-A*02:01g∼HLA-C*06:02g∼HLA-B*50:01g∼HLA-DRB1*07:01∼HLA-DQB1*02:01g at a frequency of 2.3%. The PCA demonstrated close genetic proximity of the Kuwaiti population with Middle Eastern, Southeast Asian, and North African populations in the NMDP.

CONCLUSION

Identifying the haplotype diversity in the Kuwaiti population will contribute to the selection of an HLA-match for HSCT, disease associations, pharmacogenomics, and knowledge of pop-ulation HLA diversity.

HLA Class II Allele and Haplotype Diversity in Libyans and Their Genetic Relationships with Other Populations

Background: Libya witnessed the succession of many civilizations and ethnic groups throughout history, thereby questioning the origin of present-day Libyans. Indeed, they were considered Africans given the geographical position of the country, Arabs at the cultural level, and Berbers because of the notable presence of Berber tribes. Genetic anthropology studies investigating the origin of Libyans were rarely reported, and thus little was known about the population structure of current Libyans, particularly at autosomic markers level. Methods: We examined HLA class II (DRB1, DQB1) gene profiles of 101 unrelated Libyans, and compared them with Arab-speaking communities and with Sub-Saharan and Mediterranean populations using Neighbour-Joining dendrograms, genetic distances, correspondence, and haplotype analysis. Results: Of the 42 DRB1 alleles identified, DRB1*07:01 (14.36%), DRB1*03:01 (12.38%) were the most frequent, while DQB1*02:01 (24.17%), DQB1*02:02 (13.86%), and DQB1*03:01 (12.38%) were the most frequent of the 17 DQB1 alleles detected. DRB1*03:01-DQB1*02:01 (6.93%), DRB1*07:01-DQB1*02:02 (4.45%), and DRB1*04:03-DQB1*03:02 (3.46%) were the most frequent DRB1-DQB1 haplotypes. Conclusion: Libyans appear to be closely related to North Africans, Saudis, and Iberians, but distinct from Levantine Arabs, East Mediterraneans, and Sub-Saharan Africans. This indicates limited genetic contribution of Levantine Arabs and Sub-Saharans on the makeup of Libyan gene pool. Our study confirmed genetic heterogeneity among Arab populations, with three identified groups. The first comprises North Africans, Saudis, and Kuwaitis who were related to Iberians and West Mediterraneans, while the second consists of Levantine Arabs who were close to East Mediterraneans, and the third contained Sudanese and Comorians, with a close relatedness to Sub-Saharans.

Clinical and Serologic Characteristics of Systemic Lupus Erythematosus in the Arab World: A Pooled Analysis of 3,273 Patients

OBJECTIVES

This study aims to describe the clinical and immunological characteristics of systemic lupus erythematosus in the Arab world.

MATERIALS AND METHODS

We searched PubMed and Google Scholar for observational studies describing the clinical and serologic features of systemic lupus erythematosus in adult patients in the Arab world. We used the search terms "lupus in Arabs" and the names of individual Arab countries. Twenty-two articles from 11 countries including 3,273 patients (349 males, 2,924 females; mean age 28.9 years) met the inclusion criteria and were analyzed. Studies that reported on either clinical or serologic data in adult patients were included.

RESULTS

The mean age at disease onset was 28.9 years. The female to male ratio was 8.34:1. The most common clinical manifestations were arthralgia/arthritis (81.1%), anemia (55.6%), fatigue (53.4%), malar rash (53.1%) and renal manifestations (50.4%). Antinuclear antibodies were present in 97.2%, anti-double stranded deoxyribonucleic acid in 74.1%, anti-Ro/Sjögren syndrome A in 50.5%, anti-ribonucleoprotein in 43.5%, anti-Smith in 40.7% and anti-La/Sjögren syndrome B in 29.2%. The mortality rate was 7.6%. The frequency of various clinical and immunological manifestations varied between different regions.

CONCLUSION

Systemic lupus erythematosus displays several different clinical and serologic characteristics, both among different Arab populations and in comparison to other ethnic groups.

Genetics and genomic medicine in Tunisia

Genetics and genomic medicine in Tunisia.

Association of HLA-DRB1 and -DQB1 alleles with type 1 (autoimmune) diabetes in African Arabs: systematic review and meta-analysis

Several studies confirmed the association of HLA-DRB1 and -DQB1 alleles with altered risk of type 1 diabetes (T1D). However, data from individual studies based on small sample sizes yielded often conflicting findings in African Arabs. This is a systematic review and meta-analysis aimed at comprehensively evaluating this association with T1D, using molecular HLA data. Relevant studies were identified through systemic search of Medline/PubMed, Cochrane, Science Direct, ResearchGate, and EMBASE databases. Statistical analysis was carried out using RevMan, and Comprehensive Meta-analysis programs. Given the heterogeneity of African Arabs, we also performed subgroup analysis according to ethnicity. Analysis of sensitivity, heterogeneity, and publication bias were performed to validate the outcome of the findings. This meta-analysis included 862 T1DM cases, along with 1,390 normoglycemic control, and comprised ten comparisons. Our study indicates that DRB1*03 (OR = 2.86), DRB1*04 (OR = 2.78), and DQB1*02 (OR = 2.29), are positively associated with increased risk of T1DM, while DRB1*07 (OR = 0.48), DRB1*11 (OR = 0.20), DRB1*13 (OR = 0.47), DRB1*15 (OR = 0.30), DQB1*05 (OR = 0.39), and DQB1*06 (OR = 0.27) were negatively associated with T1D, suggesting a protective role against T1D. This meta-analysis was characterized by low heterogeneity, sensitivity, and publication bias, indicating the robustness and reliability of the results.

BACKGROUND

Several studies confirmed the association of HLA-DRB1 and -DQB1 alleles with altered risk of type 1 diabetes (T1D). However, data from individual studies based on small sample sizes yielded often conflicting findings in African Arabs. This is a systematic review and meta-analysis aimed at comprehensively evaluating this association with T1D, using molecular HLA data.

METHODS

Relevant studies were identified through systemic search of Medline/PubMed, Cochrane, Science Direct, ResearchGate, and EMBASE databases. Statistical analysis was carried out using Revman, and Comprehensive Meta-analysis programs. Given the heterogeneity of African Arabs, we also performed subgroup analysis according to ethnicity. Analysis of sensitivity, heterogeneity, and pub¬lication bias were performed to validate the outcome of the findings. This meta-analysis included 862 T1DM cases, along with 1,390 normoglycemic control, and comprised ten comparisons.

RESULTS

Our study indicates that DRB1*03 (OR = 2.86), DRB1*04 (OR = 2.78), and DQB1*02 (OR = 2.29), are positively associated with increased risk of T1DM, while DRB1*07 (OR = 0.48), DRB1*11 (OR = 0.20), DRB1*13 (OR = 0.47), DRB1*15 (OR = 0.30), DQB1*05 (OR = 0.39), and DQB1*06 (OR = 0.27) were negatively associated with T1D, suggesting a protective role against T1D.

CONCLUSION

This meta-analysis was characterized by low heterogeneity, sensitivity, and publication bias, indicating the robustness and reliability of the results.

The genetic heterogeneity of Arab populations as inferred from HLA genes

This is the first genetic anthropology study on Arabs in MENA (Middle East and North Africa) region. The present meta-analysis included 100 populations from 36 Arab and non-Arab communities, comprising 16,006 individuals, and evaluates the genetic profile of Arabs using HLA class I (A, B) and class II (DRB1, DQB1) genes. A total of 56 Arab populations comprising 10,283 individuals were selected from several databases, and were compared with 44 Mediterranean, Asian, and sub-Saharan populations. The most frequent alleles in Arabs are A*01, A*02, B*35, B*51, DRB1*03:01, DRB1*07:01, DQB1*02:01, and DQB1*03:01, while DRB1*03:01-DQB1*02:01 and DRB1*07:01-DQB1*02:02 are the most frequent class II haplotypes. Dendrograms, correspondence analyses, genetic distances, and haplotype analysis indicate that Arabs could be stratified into four groups. The first consists of North Africans (Algerians, Tunisians, Moroccans, and Libyans), and the first Arabian Peninsula cluster (Saudis, Kuwaitis, and Yemenis), who appear to be related to Western Mediterraneans, including Iberians; this might be explained for a massive migration into these areas when Sahara underwent a relatively rapid desiccation, starting about 10,000 years BC. The second includes Levantine Arabs (Palestinians, Jordanians, Lebanese, and Syrians), along with Iraqi and Egyptians, who are related to Eastern Mediterraneans. The third comprises Sudanese and Comorians, who tend to cluster with Sub-Saharans. The fourth comprises the second Arabian Peninsula cluster, made up of Omanis, Emiratis, and Bahrainis. It is noteworthy that the two large minorities (Berbers and Kurds) are indigenous (autochthonous), and are not genetically different from "host" and neighboring populations. In conclusion, this study confirmed high genetic heterogeneity among present-day Arabs, and especially those of the Arabian Peninsula.

The HLA-B landscape of Africa: Signatures of pathogen-driven selection and molecular identification of candidate alleles to malaria protection

Human leukocyte antigen (HLA) genes play a key role in the immune response to infectious diseases, some of which are highly prevalent in specific environments, like malaria in sub-Saharan Africa. Former case-control studies showed that one particular HLA-B allele, B*53, was associated with malaria protection in Gambia, but this hypothesis was not tested so far within a population genetics framework. In this study, our objective was to assess whether pathogen-driven selection associated with malaria contributed to shape the HLA-B genetic landscape of Africa. To that aim, we first typed the HLA-A and -B loci in 484 individuals from 11 populations living in different environments across the Sahel, and we analysed these data together with those available for 29 other populations using several approaches including linear modelling on various genetic, geographic and environmental parameters. In addition to relevant signatures of populations' demography and migrations history in the genetic differentiation patterns of both HLA-A and -B loci, we found that the frequencies of three HLA alleles, B*53, B*78 and A*74, were significantly associated with Plasmodium falciparum malaria prevalence, suggesting their increase through pathogen-driven selection in malaria-endemic environments. The two HLA-B alleles were further identified, by high-throughput sequencing, as B*53:01:01 (in putative linkage disequilibrium with one HLA-C allele, C*04:01:01:01) and B*78:01 in all but one individuals tested, making them appropriate candidates to malaria protection. These results highlight the role of environmental factors in the evolution of the HLA polymorphism and open key perspectives for functional studies focusing on HLA peptide-binding properties.

Anthropological analysis of Tunisian populations as inferred from HLA class I and class II genetic diversity: A meta-analysis

Despite their importance, anthropological meta-analyses which allow for comprehensive evaluation of the relationships of a given population were rare. This meta-analysis evaluates the origin of Tunisians using polymorphic profile of HLA class I (A, B), and class II (DRB1, DQB1) genes, in historical, social and cultural context, and is the only analysis in the Middle East-North Africa (MENA) region. A total of 20 eligible populations were selected from several databases, and included representing 2553 Tunisian individuals, who were compared with Mediterranean and sub-Saharan populations. In total, 204 HLA alleles were detected in Tunisians, which comprised 54 HLA-A, 76 HLA-B, 50 DRB1, and 24 DQB1 alleles. The most frequent alleles were A*02:01(24.72%) in Berbers of Zrawa, B*50:01 (13.90.11%) in Tunisian-So, DRB1*07:01 (28.66%) in Ghannouchians, and DQB1*02:01 (42.79%) in Tunisians-H. The A, B, DRB, and DQB1 genotypes of 420 individuals were further subjected to a selection study. Despite the relatively large sample size, the loci depicted non-significant negative Fnd values, an indication of overall trend to balancing selection or gene flow. Except for Berbers of Djerba, dendrograms, correspondence analyses, genetic distances and haplotype analysis demonstrated the close relatedness of Berbers, Southern and Northern Tunisians, and strong relatedness was evident to Western Mediterranean, North African and Iberian populations, but not Sub-Saharans and Eastern Mediterranean populations, including Arabs. Collectively, this suggests that the contribution of Arabs and sub-Saharans to the present Tunisian gene pool is low. In addition, all Mediterranean populations depict a typical Mediterranean substratum, except for Greeks.

The investigation of the origin of Southern Tunisians using HLA genes

The south of Tunisia is characterized by marked ethnic diversity, highlighted by the coexistence of native Berbers with Blacks, Jews and Arab-speaking populations. Despite this heterogeneity, genetic anthropology studies investigating the origin of current Southern Tunisians were rarely reported. We examined human leukocyte antigen (HLA) class I (A, B) and class II (DRB1, DQB1) gene profiles of 250 unrelated Southern Tunisians, and compared them with those of Arab-speaking communities, along with Mediterranean and sub-Sahara African populations using genetic distances, neighbor-joining dendrograms, correspondence and haplotype analysis. In total, 137 HLA alleles were detected, which comprised 32 HLA-A, 52 HLA-B, 32 DRB1 and 21 DQB1 alleles. The most frequent alleles were HLA-A*02:01(18.02%), HLA-B*50:01 (9.11%), HLA-DRB1*07:01 (22.06%) and HLA-DQB1*02:01 (17.21%). All pairs of HLA loci show significant linkage disequilibrium. The four loci depict negative F_nd (the normalized deviate of the homozygosity) values indicating an overall trend to balancing selection. Southern Tunisians appear to be closely related to others Tunisian populations including Berbers, North Africans and Iberians. On the contrary, Southern Tunisians were distinct from Palestinian, Lebanese and Jordanian Middle Eastern Arab-speaking population, despite the deep Arab incursions and Arabization that affected Southern Tunisia. In addition, Southern Tunisians were distant from many sub-Saharan communities, evidenced by genetic distance analysis. Collectively, this indicates a limited genetic contribution of Arab invasion and Black caravans on the makeup of Southern Tunisian gene pool.

Distribution of HLA DRB1 and DQB1 alleles and DRB1-DQB1 haplotypes among Bahraini women with polycystic ovary syndrome

OBJECTIVE

This study investigated the association between HLA-DRB1 and -DQB1 alleles and DRB1-DQB1 haplotypes, and polycystic ovary syndrome (PCOS) in Bahraini women.

DESIGN

Case-control, retrospective study.

METHODS

Study subjects comprised 80 women with PCOS, and 169 age- and ethnically-matched control women. DRB1 and DQB1 genotyping was done by PCR-SSP.

RESULTS

Of the 13 DRB1 alleles and 5 DQB1 alleles identified, DRB1*10 (14.3% vs. 4.4%) and DRB1*14 (8.7% vs. 1.1%), along with DQB1*05 (35.0% vs. 23.9%), were the most frequent alleles in cases, while DRB1*11 (15.3% vs. 6.8%) was the frequent allele found in controls. The association of PCOS with DRB1*10 (Pc<0.001), DRB1*14 (Pc<0.001), DQB1*05 (Pc=0.040), but not DRB1*11 (Pc=0.076) persisted after correcting for multiple comparisons. DRB1-DQB1 haplotype analysis identified nine common shared haplotypes in women with PCOS and control women, with a frequency exceeding 1%. Significantly higher frequency of DRB1*10-DQB1*05 (12.4% vs. 3.1%) and DRB1*14-DQB1*03 (5.6% vs. 1.0%), and reduced frequency of DRB1*11-DQB1*03 (4.1% vs. 14.1%) haplotypes were seen in women with PCOS vs. control women, thus assigning PCOS-susceptible and -protective nature to these haplotypes, respectively. This association persisted after controlling for multiple comparisons.

CONCLUSION

Our results confirm an association of HLA-DRB1 and -DQB1 alleles and haplotypes with PCOS susceptibility in Bahraini Arabs, further underscoring the immunological/inflammatory nature of this disorder.

Frequency of HLA-DRB1 and HLA-DQB1 Alleles and Haplotype Association in Syrian Population

The study of Human Leukocyte Antigen (HLA) system is very important in health and diseases. As the HLA loci are the most polymorphic in the human genome, it plays a very important role in the immune responses to self and nonself antigens. In the light of the growing importance of typing the HLA alleles in transplantation, autoimmune diseases, cancer, and many other diseases, we studied 225 unrelated healthy Syrian subjects for their HLA class II genotypes in an attempt to reveal the distribution of the HLA (DRB1-DQB1) alleles in the general Syrian population. Our results revealed that the most common alleles for the DRB1 locus were DRB1*11 (26.4%), DRB1*04 (14%), and DRB1*07 (12%). However, the most frequent alleles for the DQB1 locus were DQB1*03 (40.9%) and DQB1*05 (25.1%). The frequent of two-locus haplotypes carry the most frequent alleles at these loci. The most frequently detected class II ''haplotypes'' are DRB1*11-DQB1*03 (8.9%), DRB1*01-DQB1*05 (3.6%), and DRB1*04-DQB1*03 (2.7%). Compared with other populations, our result, deduced from the analysis of genetic distances and the construction of neighbor-joining (NJ) dendrogram, and principal component analysis (PCA) indicates that Syrians are related to Middle Eastern populations. Our data about the Syrian population will aid researchers in studying the relation of HLA class II with different diseases in a Syrian population and will add to the available international literature associated with these loci.