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Dallali H, Boukhalfa W, Kheriji N, Fassatoui M, Jmel H, Hechmi M, Gouiza I, Gharbi M, Kammoun W, Mrad M, Taoueb M, Krir A, Trabelsi H, Bahlous A, Jamoussi H, Messaoud O, Abid A, Kefi R. The first exome wide association study in Tunisia: identification of candidate loci and pathways with biological relevance for type 2 diabetes. Front Endocrinol (Lausanne) 2023; 14:1293124. [PMID: 38192426 PMCID: PMC10773763 DOI: 10.3389/fendo.2023.1293124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 11/27/2023] [Indexed: 01/10/2024] Open
Abstract
Introduction Type 2 diabetes (T2D) is a multifactorial disease involving genetic and environmental components. Several genome-wide association studies (GWAS) have been conducted to decipher potential genetic aberrations promoting the onset of this metabolic disorder. These GWAS have identified over 400 associated variants, mostly in the intronic or intergenic regions. Recently, a growing number of exome genotyping or exome sequencing experiments have identified coding variants associated with T2D. Such studies were mainly conducted in European populations, and the few candidate-gene replication studies in North African populations revealed inconsistent results. In the present study, we aimed to discover the coding genetic etiology of T2D in the Tunisian population. Methods We carried out a pilot Exome Wide Association Study (EWAS) on 50 Tunisian individuals. Single variant analysis was performed as implemented in PLINK on potentially deleterious coding variants. Subsequently, we applied gene-based and gene-set analyses using MAGMA software to identify genes and pathways associated with T2D. Potential signals were further replicated in an existing large in-silico dataset, involving up to 177116 European individuals. Results Our analysis revealed, for the first time, promising associations between T2D and variations in MYORG gene, implicated in the skeletal muscle fiber development. Gene-set analysis identified two candidate pathways having nominal associations with T2D in our study samples, namely the positive regulation of neuron apoptotic process and the regulation of mucus secretion. These two pathways are implicated in the neurogenerative alterations and in the inflammatory mechanisms of metabolic diseases. In addition, replication analysis revealed nominal associations of the regulation of beta-cell development and the regulation of peptidase activity pathways with T2D, both in the Tunisian subjects and in the European in-silico dataset. Conclusions The present study is the first EWAS to investigate the impact of single genetic variants and their aggregate effects on T2D risk in Africa. The promising disease markers, revealed by our pilot EWAS, will promote the understanding of the T2D pathophysiology in North Africa as well as the discovery of potential treatments.
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Affiliation(s)
- Hamza Dallali
- Genetic typing service, Institut Pasteur of Tunis, Tunis, Tunisia
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur of Tunis, Tunis, Tunisia
- University of Tunis El Manar, Tunis, Tunisia
| | - Wided Boukhalfa
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur of Tunis, Tunis, Tunisia
- University of Tunis El Manar, Tunis, Tunisia
- Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Nadia Kheriji
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur of Tunis, Tunis, Tunisia
- University of Tunis El Manar, Tunis, Tunisia
- Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Meriem Fassatoui
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur of Tunis, Tunis, Tunisia
| | - Haifa Jmel
- Genetic typing service, Institut Pasteur of Tunis, Tunis, Tunisia
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur of Tunis, Tunis, Tunisia
- University of Tunis El Manar, Tunis, Tunisia
| | - Meriem Hechmi
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur of Tunis, Tunis, Tunisia
| | - Ismail Gouiza
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur of Tunis, Tunis, Tunisia
- University of Tunis El Manar, Tunis, Tunisia
- Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
- MitoLab Team, Unité MitoVasc, UMR CNRS 6015, INSERM U1083, SFR ICAT, University of Angers, Angers, France
| | - Mariem Gharbi
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur of Tunis, Tunis, Tunisia
- University of Tunis El Manar, Tunis, Tunisia
- Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Wafa Kammoun
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur of Tunis, Tunis, Tunisia
| | - Mehdi Mrad
- Laboratory of Clinical Biochemistry and Hormonology, Institut Pasteur of Tunis, Tunis, Tunisia
| | - Marouen Taoueb
- Laboratory of Clinical Biochemistry and Hormonology, Institut Pasteur of Tunis, Tunis, Tunisia
| | - Asma Krir
- Laboratory of Clinical Biochemistry and Hormonology, Institut Pasteur of Tunis, Tunis, Tunisia
| | - Hajer Trabelsi
- Laboratory of Clinical Biochemistry and Hormonology, Institut Pasteur of Tunis, Tunis, Tunisia
| | - Afef Bahlous
- Laboratory of Clinical Biochemistry and Hormonology, Institut Pasteur of Tunis, Tunis, Tunisia
| | - Henda Jamoussi
- Research Unit on Obesity, Faculty of Medicine of Tunis, Tunis, Tunisia
| | - Olfa Messaoud
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur of Tunis, Tunis, Tunisia
- University of Tunis El Manar, Tunis, Tunisia
| | - Abdelmajid Abid
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur of Tunis, Tunis, Tunisia
| | - Rym Kefi
- Genetic typing service, Institut Pasteur of Tunis, Tunis, Tunisia
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur of Tunis, Tunis, Tunisia
- University of Tunis El Manar, Tunis, Tunisia
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Dashti M, Nizam R, John SE, Melhem M, Channanath A, Alkandari H, Thanaraj TA, Al-Mulla F. ONECUT1 variants beyond type 1 and type 2 diabetes: exploring clinical diversity and epigenetic associations in Arab cohorts. Front Genet 2023; 14:1254833. [PMID: 37941991 PMCID: PMC10628528 DOI: 10.3389/fgene.2023.1254833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 10/11/2023] [Indexed: 11/10/2023] Open
Abstract
ONECUT1 gene, encoding hepatocyte nuclear factor 6, is involved in pancreas and liver development. ONECUT1 mutations impair the function of pancreatic β-cells and control a transcriptional/epigenetic machinery regulating endocrine development. Homozygous nonsense and missense mutations at ONECUT1_p.E231 and a homozygous frameshift mutation at ONECUT1_p.M289 were reported in neonatal diabetes individuals of French, Turkish, and Indian ethnicity, respectively. Additionally, heterozygous variants were observed in Northern European T2D patients, and Italian patients with neonatal diabetes and early-/late-onset T2D. Examining diverse populations, such as Arabs known for consanguinity, can generalize the ONECUT1 involvement in diabetes. Upon screening the cohorts of Kuwaiti T1D and MODY families, and of Kuwaiti and Qatari T2D individuals, we observed two homozygous variants-the deleterious missense rs202151356_p.H33Q in one MODY, one T1D, and two T2D individuals, and the synonymous rs61735385_p.P94P in two T2D individuals. Heterozygous variants were also observed. Examination of GTEx, NephQTL, mQTLdb and HaploReg highlighted the rs61735385_p.P94P variant as eQTL influencing the tissue-specific expression of ONECUT1, as mQTL influencing methylation at CpG sites in and around ONECUT1 with the nearest site at 677-bases 3' to rs61735385_p.P94P; as overlapping predicted binding sites for NF-kappaB and EBF on ONECUT1. DNA methylation profiles of peripheral blood from 19 MODY-X patients versus eight healthy individuals revealed significant hypomethylation at two CpG sites-one located 617-bases 3' to the p.P94P variant and 8,102 bases away from transcription start; and the other located 14,999 bases away from transcription start. Our study generalizes the association of ONECUT1 with clinical diversity in diabetes.
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Affiliation(s)
- Mohammed Dashti
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Rasheeba Nizam
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Sumi Elsa John
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Motasem Melhem
- Department of Specialized Services Facility, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Arshad Channanath
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Hessa Alkandari
- Department of Population Health, Dasman Diabetes Institute, Kuwait City, Kuwait
- Department of Pediatrics, Farwaniya Hospital, Ministry of Health, Kuwait City, Kuwait
| | | | - Fahd Al-Mulla
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Kuwait City, Kuwait
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Mezzavilla M, Cocca M, Maisano Delser P, Badii R, Abbaszadeh F, Hadi KA, Giorgia G, Gasparini P. Ancestry-related distribution of Runs of homozygosity and functional variants in Qatari population. BMC Genom Data 2022; 23:73. [PMID: 36131251 PMCID: PMC9490902 DOI: 10.1186/s12863-022-01087-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 08/29/2022] [Indexed: 11/16/2022] Open
Abstract
Background Describing how genetic history shapes the pattern of medically relevant variants could improve the understanding of how specific loci interact with each other and affect diseases and traits prevalence. The Qatari population is characterized by a complex history of admixture and substructure, and the study of its population genomic features would provide valuable insights into the genetic landscape of functional variants. Here, we analyzed the genomic variation of 186 newly-genotyped healthy individuals from the Qatari peninsula. Results We discovered an intricate genetic structure using ancestry related analyses. In particular, the presence of three different clusters, Cluster 1, Cluster 2 and Cluster 3 (with Near Eastern, South Asian and African ancestry, respectively), was detected with an additional fourth one (Cluster 4) with East Asian ancestry. These subpopulations show differences in the distribution of runs of homozygosity (ROH) and admixture events in the past, ranging from 40 to 5 generations ago. This complex genetic history led to a peculiar pattern of functional markers under positive selection, differentiated in shared signals and private signals. Interestingly we found several signatures of shared selection on SNPs in the FADS2 gene, hinting at a possible common evolutionary link to dietary intake. Among the private signals, we found enrichment for markers associated with HDL and LDL for Cluster 1(Near Eastern ancestry) and Cluster 3 (South Asian ancestry) and height and blood traits for Cluster 2 (African ancestry). The differences in genetic history among these populations also resulted in the different frequency distribution of putative loss of function variants. For example, homozygous carriers for rs2884737, a variant linked to an anticoagulant drug (warfarin) response, are mainly represented by individuals with predominant Bedouin ancestry (risk allele frequency G at 0.48). Conclusions We provided a detailed catalogue of the different ancestral pattern in the Qatari population highlighting differences and similarities in the distribution of selected variants and putative loss of functions. Finally, these results would provide useful guidance for assessing genetic risk factors linked to consanguinity and genetic ancestry.
Supplementary Information The online version contains supplementary material available at 10.1186/s12863-022-01087-1.
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Rodriguez-Flores JL, Messai-Badji R, Robay A, Temanni R, Syed N, Markovic M, Al-Khayat E, Qafoud F, Nawaz Z, Badii R, Al-Sarraj Y, Mbarek H, Al-Muftah W, Alvi M, Rostami MR, Cruzado JCM, Mezey JG, Shakaki AA, Malek JA, Greenblatt MB, Fakhro KA, Machaca K, Al-Nabet A, Afifi N, Brooks A, Ismail SI, Althani A, Crystal RG. The QChip1 knowledgebase and microarray for precision medicine in Qatar. NPJ Genom Med 2022; 7:3. [PMID: 35046417 PMCID: PMC8770564 DOI: 10.1038/s41525-021-00270-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 11/04/2021] [Indexed: 12/28/2022] Open
Abstract
Risk genes for Mendelian (single-gene) disorders (SGDs) are consistent across populations, but pathogenic risk variants that cause SGDs are typically population-private. The goal was to develop "QChip1," an inexpensive genotyping microarray to comprehensively screen newborns, couples, and patients for SGD risk variants in Qatar, a small nation on the Arabian Peninsula with a high degree of consanguinity. Over 108 variants in 8445 Qatari were identified for inclusion in a genotyping array containing 165,695 probes for 83,542 known and potentially pathogenic variants in 3438 SGDs. QChip1 had a concordance with whole-genome sequencing of 99.1%. Testing of QChip1 with 2707 Qatari genomes identified 32,674 risk variants, an average of 134 pathogenic alleles per Qatari genome. The most common pathogenic variants were those causing homocystinuria (1.12% risk allele frequency), and Stargardt disease (2.07%). The majority (85%) of Qatari SGD pathogenic variants were not present in Western populations such as European American, South Asian American, and African American in New York City and European and Afro-Caribbean in Puerto Rico; and only 50% were observed in a broad collection of data across the Greater Middle East including Kuwait, Iran, and United Arab Emirates. This study demonstrates the feasibility of developing accurate screening tools to identify SGD risk variants in understudied populations, and the need for ancestry-specific SGD screening tools.
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Affiliation(s)
- Juan L Rodriguez-Flores
- Department of Genetic Medicine, Weill Cornell Medicine, New York, NY, USA
- Regeneron Genetics Center, Tarrytown, NY, USA
| | | | | | - Ramzi Temanni
- Department of Human Genetics, Sidra Medicine, Doha, Qatar
| | - Najeeb Syed
- Department of Human Genetics, Sidra Medicine, Doha, Qatar
| | - Monika Markovic
- Qatar Biobank for Medical Research, Qatar Foundation, Doha, Qatar
| | - Eiman Al-Khayat
- Qatar Biobank for Medical Research, Qatar Foundation, Doha, Qatar
| | - Fatima Qafoud
- Qatar Biobank for Medical Research, Qatar Foundation, Doha, Qatar
| | - Zafar Nawaz
- Diagnostic Genomic Division, Hamad Medical Corporation, Doha, Qatar
| | - Ramin Badii
- Weill Cornell Medicine, Doha, Qatar
- Diagnostic Genomic Division, Hamad Medical Corporation, Doha, Qatar
| | | | - Hamdi Mbarek
- Qatar Genome Program, Qatar Foundation, Doha, Qatar
| | | | | | | | | | - Jason G Mezey
- Department of Genetic Medicine, Weill Cornell Medicine, New York, NY, USA
- Department of Computational Biology, Cornell University, Ithaca, NY, USA
| | | | | | - Matthew B Greenblatt
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Khalid A Fakhro
- Weill Cornell Medicine, Doha, Qatar
- Department of Human Genetics, Sidra Medicine, Doha, Qatar
| | | | - Ajayeb Al-Nabet
- Diagnostic Genomic Division, Hamad Medical Corporation, Doha, Qatar
| | - Nahla Afifi
- Qatar Biobank for Medical Research, Qatar Foundation, Doha, Qatar
| | - Andrew Brooks
- RUCDR Infinite Biologics, Piscataway, NJ, USA
- Department of Genetics, Rutgers University, New Brunswick, NJ, USA
| | | | - Asmaa Althani
- Qatar Genome Program, Qatar Foundation, Doha, Qatar
- Biomedical Research Center, Qatar University, Doha, Qatar
| | - Ronald G Crystal
- Department of Genetic Medicine, Weill Cornell Medicine, New York, NY, USA.
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Genome-wide association study identifies novel risk variants from RPS6KA1, CADPS, VARS, and DHX58 for fasting plasma glucose in Arab population. Sci Rep 2020; 10:152. [PMID: 31932636 PMCID: PMC6957513 DOI: 10.1038/s41598-019-57072-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 12/20/2019] [Indexed: 12/14/2022] Open
Abstract
Consanguineous populations of the Arabian Peninsula, which has seen an uncontrolled rise in type 2 diabetes incidence, are underrepresented in global studies on diabetes genetics. We performed a genome-wide association study on the quantitative trait of fasting plasma glucose (FPG) in unrelated Arab individuals from Kuwait (discovery-cohort:n = 1,353; replication-cohort:n = 1,196). Genome-wide genotyping in discovery phase was performed for 632,375 markers from Illumina HumanOmniExpress Beadchip; and top-associating markers were replicated using candidate genotyping. Genetic models based on additive and recessive transmission modes were used in statistical tests for associations in discovery phase, replication phase, and meta-analysis that combines data from both the phases. A genome-wide significant association with high FPG was found at rs1002487 (RPS6KA1) (p-discovery = 1.64E-08, p-replication = 3.71E-04, p-combined = 5.72E-11; β-discovery = 8.315; β-replication = 3.442; β-combined = 6.551). Further, three suggestive associations (p-values < 8.2E-06) with high FPG were observed at rs487321 (CADPS), rs707927 (VARS and 2Kb upstream of VWA7), and rs12600570 (DHX58); the first two markers reached genome-wide significance in the combined analysis (p-combined = 1.83E-12 and 3.07E-09, respectively). Significant interactions of diabetes traits (serum triglycerides, FPG, and glycated hemoglobin) with homeostatic model assessment of insulin resistance were identified for genotypes heterozygous or homozygous for the risk allele. Literature reports support the involvement of these gene loci in type 2 diabetes etiology.
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Dakroury Y, Atkin SL, Dargham SR, Robay A, Rodriguez-Flores J, Crystal RG, Butler AE. Qatari Genotype May Contribute to Complications in Type 2 Diabetes. J Diabetes Res 2020; 2020:6356973. [PMID: 32587868 PMCID: PMC7303741 DOI: 10.1155/2020/6356973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 05/13/2020] [Accepted: 05/20/2020] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE There is increasing evidence of a strong genetic component in type 2 diabetes (T2DM) that may contribute to diabetes complications. Given the high prevalence of diabetes with its associated complications in the Middle East, we sought to determine if the genotype within a Middle East population may be contributory. Therefore, three genotype-based Qatari ancestral groups, Q1 Arab Bedouin, Q2 Asian/Persian, and Q3 sub-Saharan African, with a fourth admixed group were correlated with T2DM prevalence and its complications to determine if they differed between the 4 Qatari ancestries, particularly for the SLMAP allele-associated diabetic retinopathy. METHODS In this cross-sectional study, 398 Qatari subjects, 220 with and 178 without T2DM, were genotyped by Affymetrix 500k SNP arrays. Ancestry was correlated with diabetes complications. RESULTS 398 subjects were included, the mean age was 49.8 years, and 56.8% were male. The genotype-based ancestry and T2DM prevalence were as follows: 164 (41.2%) with ancestry Q1, 60.4% with T2DM; 149 (37.4%) with ancestry Q2, 49.7% with T2DM; 31 (7.8%) with ancestry Q3, 61.3% with T2DM; and 54 (13.6%) with "admixed" ancestry, 51.9% with T2DM. For patients with diabetes, hypertension (p < 0.035) and retinopathy (p < 0.016) were greater in the Q3 ancestry. CONCLUSION These data suggest that the genotype may contribute to complication risk, as exemplified by the increase in hypertension and retinopathy in the Q3 ancestry, though the SLMAP allele was not implicated; however, diabetes prevalence did not differ between the four Qatari ancestries.
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Affiliation(s)
| | | | | | - Amal Robay
- Weill Cornell Medicine-Qatar, PO Box 24144, Doha, Qatar
| | | | - Ronald G. Crystal
- Department of Genetic Medicine, Weill Cornell Medicine, New York, USA
| | - Alexandra E. Butler
- Diabetes Research Center (DRC), Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha, Qatar
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