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Alper CA, Dawkins RL, Kulski JK, Larsen CE, Lloyd SS. Editorial: Population genomic architecture: Conserved polymorphic sequences (CPSs), not linkage disequilibrium. Front Genet 2023; 14:1140350. [PMID: 36777737 PMCID: PMC9911302 DOI: 10.3389/fgene.2023.1140350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 01/17/2023] [Indexed: 01/28/2023] Open
Affiliation(s)
- Chester A. Alper
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA, United States,Department of Pediatrics, Harvard Medical School, Boston, MA, United States,*Correspondence: Chester A. Alper, ; Roger L. Dawkins, ; Jerzy K. Kulski, ; Charles E. Larsen, ; Sally S. Lloyd,
| | - Roger L. Dawkins
- CY O’Connor ERADE Village Foundation, North Dandalup, WA, Australia,*Correspondence: Chester A. Alper, ; Roger L. Dawkins, ; Jerzy K. Kulski, ; Charles E. Larsen, ; Sally S. Lloyd,
| | - Jerzy K. Kulski
- Department of Molecular Life Sciences, Division of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, Isehara, Japan,*Correspondence: Chester A. Alper, ; Roger L. Dawkins, ; Jerzy K. Kulski, ; Charles E. Larsen, ; Sally S. Lloyd,
| | - Charles E. Larsen
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA, United States,Department of Pediatrics, Harvard Medical School, Boston, MA, United States,*Correspondence: Chester A. Alper, ; Roger L. Dawkins, ; Jerzy K. Kulski, ; Charles E. Larsen, ; Sally S. Lloyd,
| | - Sally S. Lloyd
- CY O’Connor ERADE Village Foundation, North Dandalup, WA, Australia,*Correspondence: Chester A. Alper, ; Roger L. Dawkins, ; Jerzy K. Kulski, ; Charles E. Larsen, ; Sally S. Lloyd,
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Alper CA. The Path to Conserved Extended Haplotypes: Megabase-Length Haplotypes at High Population Frequency. Front Genet 2021; 12:716603. [PMID: 34422017 PMCID: PMC8378214 DOI: 10.3389/fgene.2021.716603] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/13/2021] [Indexed: 11/13/2022] Open
Abstract
This minireview describes the history of the conceptual development of conserved extended haplotypes (CEHs): megabase-length haplotypes that exist at high (≥0.5%) population frequency. My career began in internal medicine, shifted to pediatrics, and clinical practice changed to research. My research interest was initially in hematology: on plasma proteins, their metabolism, synthesis, and function. This narrowed to a focus on proteins of the human complement system, their role in immunity and their genetics, beginning with polymorphism and deficiency of C3. My group identified genetic polymorphisms and/or inherited deficiencies of C2, C4, C6, and C8. After defining glycine-rich beta glycoprotein as factor B (Bf) in the properdin system, we found that the genes for Bf (CFB), C2, C4A, and C4B were inherited as a single haplotypic unit which we named the "complotype." Complotypes are located within the major histocompatibility complex (MHC) between HLA-B and HLA-DRB1 and are designated (in arbitrary order) by their CFB, C2, C4A, and C4B types. Pedigree analysis revealed long stretches (several megabases) of apparently fixed DNA within the MHC that we referred to as "extended haplotypes" (later as "CEHs"). About 10 to 12 common CEHs constitute at least 25 - 30% of MHC haplotypes among European Caucasian populations. These CEHs contain virtually all the most common markers of MHC-associated diseases. In the case of type 1 diabetes, we have proposed a purely genetic and epigenetic model (with a small number of Mendelian recessive disease genes) that explains all the puzzling features of the disease, including its rising incidence.
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Affiliation(s)
- Chester A Alper
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, United States.,Department of Pediatrics, Harvard Medical School, Boston, MA, United States
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Tay GK, Al Naqbi H, Mawart A, Baalfaqih Z, Almaazmi A, Deeb A, Alsafar H. Segregation Analysis of Genotyped and Family-Phased, Long Range MHC Classical Class I and Class II Haplotypes in 5 Families With Type 1 Diabetes Proband in the United Arab Emirates. Front Genet 2021; 12:670844. [PMID: 34276777 PMCID: PMC8278101 DOI: 10.3389/fgene.2021.670844] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 06/09/2021] [Indexed: 12/16/2022] Open
Abstract
The classical Human Leucocyte Antigen (HLA) class II haplotypes of the Major Histocompatibility Complex (MHC) that are associated with type 1 diabetes (T1D) were identified in five families from the United Arab Emirates (UAE). Segregation analyses were performed on these 5 families with the disease, 3 with one child and 2 with 2 children diagnosed with T1D. Three HLA-DR4 haplotypes were identified: HLA- DRB1∗04:01:01-DQB1∗03:02:01:01; HLA- DRB1∗04:02:01- DQB1∗03:02:01; and HLA -DRB1∗04:05:01-DQB1∗02:02:01:02. All have previously been identified to be associated with T1D in studies of the Arabian population. In the 10 parents from the 5 families, 9 had at least one HLA-DR4 and HLA-DR3 haplotype which potentially increases the risk of T1D. Of these 9 parents, 3 were heterozygous for HLA-DR4/HLA-DR3 and one was homozygous for HLA-DR3. Two haplotypes that were identified here extend to the HLA class I region were previously designated AH8.2 (HLA -A∗26-B∗08-DRB1∗03) and AH50.2 (HLA -C∗06-B∗50-DRB1∗03:01-DQ∗02) and associated with diabetes in neighboring North Indian populations. This study provides examples of MHC haplotype analysis in pedigrees to improve our understanding of the genetics of T1D in the understudied population of the UAE.
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Affiliation(s)
- Guan K Tay
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates.,Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates.,Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates.,Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates.,Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Halima Al Naqbi
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Aurélie Mawart
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Zahrah Baalfaqih
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Anoud Almaazmi
- College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Asma Deeb
- Department of Endocrinology, Mafraq Hospital, Abu Dhabi, United Arab Emirates
| | - Habiba Alsafar
- Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates.,Department of Biomedical Engineering, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates.,College of Medicine and Health Sciences, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
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Vadva Z, Larsen CE, Propp BE, Trautwein MR, Alford DR, Alper CA. A New Pedigree-Based SNP Haplotype Method for Genomic Polymorphism and Genetic Studies. Cells 2019; 8:E835. [PMID: 31387299 PMCID: PMC6721696 DOI: 10.3390/cells8080835] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 07/30/2019] [Accepted: 07/31/2019] [Indexed: 12/25/2022] Open
Abstract
Single nucleotide polymorphisms (SNPs) are usually the most frequent genomic variants. Directly pedigree-phased multi-SNP haplotypes provide a more accurate view of polymorphic population genomic structure than individual SNPs. The former are, therefore, more useful in genetic correlation with subject phenotype. We describe a new pedigree-based methodology for generating non-ambiguous SNP haplotypes for genetic study. SNP data for haplotype analysis were extracted from a larger Type 1 Diabetes Genetics Consortium SNP dataset based on minor allele frequency variation and redundancy, coverage rate (the frequency of phased haplotypes in which each SNP is defined) and genomic location. Redundant SNPs were eliminated, overall haplotype polymorphism was optimized and the number of undefined haplotypes was minimized. These edited SNP haplotypes from a region containing HLA-DRB1 (DR) and HLA-DQB1 (DQ) both correlated well with HLA-typed DR,DQ haplotypes and differentiated HLA-DR,DQ fragments shared by three pairs of previously identified megabase-length conserved extended haplotypes. In a pedigree-based genetic association assay for type 1 diabetes, edited SNP haplotypes and HLA-typed HLA-DR,DQ haplotypes from the same families generated essentially identical qualitative and quantitative results. Therefore, this edited SNP haplotype method is useful for both genomic polymorphic architecture and genetic association evaluation using SNP markers with diverse minor allele frequencies.
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Affiliation(s)
- Zareen Vadva
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Charles E Larsen
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA.
| | - Bennett E Propp
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Michael R Trautwein
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Dennis R Alford
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Chester A Alper
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA.
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