1
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Zimoń M, Huang Y, Trasta A, Halavatyi A, Liu JZ, Chen CY, Blattmann P, Klaus B, Whelan CD, Sexton D, John S, Huber W, Tsai EA, Pepperkok R, Runz H. Pairwise effects between lipid GWAS genes modulate lipid plasma levels and cellular uptake. Nat Commun 2021; 12:6411. [PMID: 34741066 PMCID: PMC8571362 DOI: 10.1038/s41467-021-26761-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 10/09/2021] [Indexed: 12/27/2022] Open
Abstract
Complex traits are characterized by multiple genes and variants acting simultaneously on a phenotype. However, studying the contribution of individual pairs of genes to complex traits has been challenging since human genetics necessitates very large population sizes, while findings from model systems do not always translate to humans. Here, we combine genetics with combinatorial RNAi (coRNAi) to systematically test for pairwise additive effects (AEs) and genetic interactions (GIs) between 30 lipid genome-wide association studies (GWAS) genes. Gene-based burden tests from 240,970 exomes show that in carriers with truncating mutations in both, APOB and either PCSK9 or LPL ("human double knock-outs") plasma lipid levels change additively. Genetics and coRNAi identify overlapping AEs for 12 additional gene pairs. Overlapping GIs are observed for TOMM40/APOE with SORT1 and NCAN. Our study identifies distinct gene pairs that modulate plasma and cellular lipid levels primarily via AEs and nominates putative drug target pairs for improved lipid-lowering combination therapies.
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Affiliation(s)
- Magdalena Zimoń
- grid.4709.a0000 0004 0495 846XMolecular Medicine Partnership Unit (MMPU), University of Heidelberg/EMBL, Heidelberg, Germany ,Cell Biology and Biophysics Unit, European Molecular Biological Laboratory, Heidelberg, Germany
| | - Yunfeng Huang
- grid.417832.b0000 0004 0384 8146Translational Biology, Biogen Inc, Cambridge, MA USA
| | - Anthi Trasta
- grid.4709.a0000 0004 0495 846XMolecular Medicine Partnership Unit (MMPU), University of Heidelberg/EMBL, Heidelberg, Germany ,Cell Biology and Biophysics Unit, European Molecular Biological Laboratory, Heidelberg, Germany
| | - Aliaksandr Halavatyi
- Advanced Light Microscopy Facility (ALMF), European Molecular Biological Laboratory, Heidelberg, Germany
| | - Jimmy Z. Liu
- grid.417832.b0000 0004 0384 8146Translational Biology, Biogen Inc, Cambridge, MA USA
| | - Chia-Yen Chen
- grid.417832.b0000 0004 0384 8146Translational Biology, Biogen Inc, Cambridge, MA USA ,grid.32224.350000 0004 0386 9924Psychiatric and Neurodevelopmental Genetics Unit, Mass General Hospital, Boston, MA USA
| | - Peter Blattmann
- grid.4709.a0000 0004 0495 846XMolecular Medicine Partnership Unit (MMPU), University of Heidelberg/EMBL, Heidelberg, Germany ,Cell Biology and Biophysics Unit, European Molecular Biological Laboratory, Heidelberg, Germany ,grid.508389.f0000 0004 6414 2411Idorsia Pharmaceuticals Ltd, Basel, Switzerland
| | - Bernd Klaus
- Genome Biology Unit, European Molecular Biological Laboratory, Heidelberg, Germany
| | - Christopher D. Whelan
- grid.417832.b0000 0004 0384 8146Translational Biology, Biogen Inc, Cambridge, MA USA
| | - David Sexton
- grid.417832.b0000 0004 0384 8146Translational Biology, Biogen Inc, Cambridge, MA USA
| | - Sally John
- grid.417832.b0000 0004 0384 8146Translational Biology, Biogen Inc, Cambridge, MA USA
| | - Wolfgang Huber
- Genome Biology Unit, European Molecular Biological Laboratory, Heidelberg, Germany
| | - Ellen A. Tsai
- grid.417832.b0000 0004 0384 8146Translational Biology, Biogen Inc, Cambridge, MA USA
| | - Rainer Pepperkok
- grid.4709.a0000 0004 0495 846XMolecular Medicine Partnership Unit (MMPU), University of Heidelberg/EMBL, Heidelberg, Germany ,Cell Biology and Biophysics Unit, European Molecular Biological Laboratory, Heidelberg, Germany ,Advanced Light Microscopy Facility (ALMF), European Molecular Biological Laboratory, Heidelberg, Germany
| | - Heiko Runz
- grid.4709.a0000 0004 0495 846XMolecular Medicine Partnership Unit (MMPU), University of Heidelberg/EMBL, Heidelberg, Germany ,grid.417832.b0000 0004 0384 8146Translational Biology, Biogen Inc, Cambridge, MA USA
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2
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Turkyilmaz A, Kurnaz E, Alavanda C, Yarali O, Kartal Baykan E, Yavuz D, Cayir A, Ata P. The Spectrum of Low-Density Lipoprotein Receptor Mutations in a Large Turkish Cohort of Patients with Familial Hypercholesterolemia. Metab Syndr Relat Disord 2021; 19:340-346. [PMID: 33794673 DOI: 10.1089/met.2021.0004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: Monogenic hypercholesterolemia with Mendelian inheritance is a heterogeneous group of diseases that are characterized by elevated plasma low-density lipoprotein cholesterol (LDL-C) levels, and the most common form of this disorder is autosomal-dominant familial hypercholesterolemia (FH). Methods: A total of 104 index cases with the clinical diagnosis of FH were included in this study. Low-density lipoprotein receptor (LDLR) was sequenced using the Sanger sequencing method. Results: Pathogenic/likely pathogenic variants were detected in LDLR in 55 of the 104 cases (mutation detection rate = 52.8%). Thirty different variants were detected in LDLR, three of which were novel. The total cholesterol and LDL-C values of the patients in the group of premature termination codon (PTC) mutation carriers were significantly higher than those of the patients in the group of non-PTC mutation carriers. A total of 87 patients (17 pediatric and 70 adult cases) were diagnosed with cascade genetic screening. Statin treatment was recommended to all 87 patients and was accepted and initiated in 70 of these patients. Conclusions: This study is the largest patient cohort that evaluated FH cases in the Turkish population. Herein, we revealed the LDLR mutation spectrum for a Turkish population and compared the cases in the context of genotype-phenotype correlation. Genetic screening of individuals with suspected FH not only helps to establish their diagnosis, but also facilitates early diagnosis and treatment initiation in other family members through cascade screening.
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Affiliation(s)
- Ayberk Turkyilmaz
- Department of Medical Genetics, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey
| | - Erdal Kurnaz
- Department of Pediatric Endocrinology, Dr. Sami Ulus Obstetrics and Gynecology, Children's Health and Disease Training and Research Hospital, Ankara, Turkey
| | - Ceren Alavanda
- Department of Medical Genetics, Marmara University School of Medicine, Istanbul, Turkey
| | - Oguzhan Yarali
- Department of Medical Genetics, Erzurum City Hospital, Erzurum, Turkey
| | | | - Dilek Yavuz
- Department of Endocrinology, Marmara University School of Medicine, Istanbul, Turkey
| | - Atilla Cayir
- Department of Pediatric Endocrinology, Erzurum City Hospital, Erzurum, Turkey
| | - Pinar Ata
- Department of Medical Genetics, Marmara University School of Medicine, Istanbul, Turkey
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3
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Kamar A, Khalil A, Nemer G. The Digenic Causality in Familial Hypercholesterolemia: Revising the Genotype-Phenotype Correlations of the Disease. Front Genet 2021; 11:572045. [PMID: 33519890 PMCID: PMC7844333 DOI: 10.3389/fgene.2020.572045] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 12/01/2020] [Indexed: 12/20/2022] Open
Abstract
Genetically inherited defects in lipoprotein metabolism affect more than 10 million individuals around the globe with preponderance in some parts where consanguinity played a major role in establishing founder mutations. Mutations in four genes have been so far linked to the dominant and recessive form of the disease. Those players encode major proteins implicated in cholesterol regulation, namely, the low-density lipoprotein receptor (LDLR) and its associate protein 1 (LDLRAP1), the proprotein convertase substilin/kexin type 9 (PCSK9), and the apolipoprotein B (APOB). Single mutations or compound mutations in one of these genes are enough to account for a spectrum of mild to severe phenotypes. However, recently several reports have identified digenic mutations in familial cases that do not necessarily reflect a much severe phenotype. Yet, data in the literature supporting this notion are still lacking. Herein, we review all the reported cases of digenic mutations focusing on the biological impact of gene dosage and the potential protective effects of single-nucleotide polymorphisms linked to hypolipidemia. We also highlight the difficulty of establishing phenotype-genotype correlations in digenic familial hypercholesterolemia cases due to the complexity and heterogeneity of the phenotypes and the still faulty in silico pathogenicity scoring system. We finally emphasize the importance of having a whole exome/genome sequencing approach for all familial cases of familial hyperlipidemia to better understand the genetic and clinical course of the disease.
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Affiliation(s)
- Amina Kamar
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Athar Khalil
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon
| | - Georges Nemer
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon
- Division of Genomics and Translational Biomedicine, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
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Novel combined variants of LDLR and LDLRAP1 genes causing severe familial hypercholesterolemia. Atherosclerosis 2019; 277:425-433. [PMID: 30270081 DOI: 10.1016/j.atherosclerosis.2018.06.878] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/29/2018] [Accepted: 06/21/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND AIMS Familial hypercholesterolemia (FH) is a predominantly autosomal dominant hereditary disorder with significant potential for expansion of coronary artery disease. METHODS To identify candidate variant/s in FH phenotype implicated genes, next-generation sequencing was performed using a targeted customized gene panel. RESULTS We recognized a 45-year-old Saudi female FH patient with double variants in the LDLR [c.1255 T > G, p.(Y419D)] and LDLRAP1 genes [c.604_605delTCinsA, p.(S202Tfs*2)]. The proband was found to be homozygous for the LDLR variant and heterozygous for the LDLRAP1 variant. Three of the proband's children were found to be double heterozygous for the LDLR/LDLRAP1 gene variant. While her other three children were heterozygous for the same single LDLR variant. Both variants were not previously reported. The variants segregation pattern correlated with the clinical picture and with the patient's lipid profile. FH severity was greater in the proband while her children did not show any clinical manifestations. The missense variant p.(Y419D) was found to be deleterious and clinically significant based on prediction identified by PolyPhen-2 and Proven. Molecular dynamics simulation was used to further analyze the effect of the variant p.(Y419D) on the structure and function of the LDLR protein. The secondary structure was investigated, as well as the solvent accessibility and stabilizing residues. The frameshift variant of the LDLRAP1 gene results in a truncated peptide that could affect the cellular internalization of LDLR/LDL complex. CONCLUSIONS The finding of the combined variants in LDLR/LDLRAP1 genes triggering a severe FH phenotype is essential to elaborate the spectrum of variants causing FH and to understand the genotype-phenotype correlation.
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Vaverkova H, Tichy L, Karasek D, Freiberger T. A case of autosomal recessive hypercholesterolemia caused by a new variant in the LDL receptor adaptor protein 1 gene. J Clin Lipidol 2019; 13:405-410. [PMID: 30876877 DOI: 10.1016/j.jacl.2019.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 11/08/2018] [Accepted: 02/10/2019] [Indexed: 01/26/2023]
Abstract
We report a new variant in the LDLRAP1 gene associated with autosomal recessive hypercholesterolemia in a woman of central European ancestry.
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Affiliation(s)
- Helena Vaverkova
- Third Department of Internal Medicine - NRE, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic.
| | - Lukas Tichy
- Department of Internal Medicine, Hematology and Oncology, Centre of Molecular Biology and Therapy, University Hospital Brno, Brno, Czech Republic
| | - David Karasek
- Third Department of Internal Medicine - NRE, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic
| | - Tomas Freiberger
- Centre for Cardiovascular Surgery and Transplantation, Brno, Czech Republic; Central European Institute of Technology and Medical Faculty, Masaryk University, Brno, Czech Republic
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6
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Benito-Vicente A, Uribe KB, Jebari S, Galicia-Garcia U, Ostolaza H, Martin C. Familial Hypercholesterolemia: The Most Frequent Cholesterol Metabolism Disorder Caused Disease. Int J Mol Sci 2018; 19:ijms19113426. [PMID: 30388787 PMCID: PMC6275065 DOI: 10.3390/ijms19113426] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 10/21/2018] [Accepted: 10/29/2018] [Indexed: 12/18/2022] Open
Abstract
Cholesterol is an essential component of cell barrier formation and signaling transduction involved in many essential physiologic processes. For this reason, cholesterol metabolism must be tightly controlled. Cell cholesterol is mainly acquired from two sources: Dietary cholesterol, which is absorbed in the intestine and, intracellularly synthesized cholesterol that is mainly synthesized in the liver. Once acquired, both are delivered to peripheral tissues in a lipoprotein dependent mechanism. Malfunctioning of cholesterol metabolism is caused by multiple hereditary diseases, including Familial Hypercholesterolemia, Sitosterolemia Type C and Niemann-Pick Type C1. Of these, familial hypercholesterolemia (FH) is a common inherited autosomal co-dominant disorder characterized by high plasma cholesterol levels. Its frequency is estimated to be 1:200 and, if untreated, increases the risk of premature cardiovascular disease. This review aims to summarize the current knowledge on cholesterol metabolism and the relation of FH to cholesterol homeostasis with special focus on the genetics, diagnosis and treatment.
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Affiliation(s)
- Asier Benito-Vicente
- Departamento de Bioquímica, Instituto Biofisika (UPV/EHU, CSIC), Universidad del País Vasco, Apdo.644, 48080 Bilbao, Spain.
| | - Kepa B Uribe
- Departamento de Bioquímica, Instituto Biofisika (UPV/EHU, CSIC), Universidad del País Vasco, Apdo.644, 48080 Bilbao, Spain.
| | - Shifa Jebari
- Departamento de Bioquímica, Instituto Biofisika (UPV/EHU, CSIC), Universidad del País Vasco, Apdo.644, 48080 Bilbao, Spain.
| | - Unai Galicia-Garcia
- Departamento de Bioquímica, Instituto Biofisika (UPV/EHU, CSIC), Universidad del País Vasco, Apdo.644, 48080 Bilbao, Spain.
| | - Helena Ostolaza
- Departamento de Bioquímica, Instituto Biofisika (UPV/EHU, CSIC), Universidad del País Vasco, Apdo.644, 48080 Bilbao, Spain.
| | - Cesar Martin
- Departamento de Bioquímica, Instituto Biofisika (UPV/EHU, CSIC), Universidad del País Vasco, Apdo.644, 48080 Bilbao, Spain.
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7
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Fahed AC, Khalaf R, Salloum R, Andary RR, Safa R, El-Rassy I, Moubarak E, Azar ST, Bitar FF, Nemer G. Variable expressivity and co-occurrence of LDLR and LDLRAP1 mutations in familial hypercholesterolemia: failure of the dominant and recessive dichotomy. Mol Genet Genomic Med 2016; 4:283-91. [PMID: 27247956 PMCID: PMC4867562 DOI: 10.1002/mgg3.203] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 12/14/2015] [Accepted: 12/17/2015] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND The familial inherited genetic disorder of lipoprotein metabolism affects more than 10 million individuals around the world. Lebanon is one of the several endemic areas for familial hypercholesterolemia (FH) with a founder mutation in the low-density lipoprotein cholesterol receptor (LDLR) gene, responsible for most of the cases. We have previously shown that 16% of all familial cases with hypercholesterolemia do not show genotype segregation of LDLR with the underlying phenotype. METHODS We used Sanger sequencing to genotype 25 Lebanese families with severe FH for the gene encoding the LDLR-associated protein (LDLRAP1), responsible for the recessive form of the disease starting with the four families that did not show any genotype-phenotype correlation in our previous screening. RESULTS We showed that the previously reported p.Q136* variant is linked to the hypercholesterolemia phenotype in the four families. In addition, we showed a variable phenotype between families and between members of the same family. One family exhibits mutations in both LDLR and LDLRAP1 with family members showing differential phenotypes unexplained by the underlying genotypes of the two genes. CONCLUSION The p.Q136* variant in LDLRAP1 is yet another founder mutation in Lebanon and coupled with the LDLR p.C681* variant explains all the genetic causes of FH in Lebanon.
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Affiliation(s)
- Akl C Fahed
- Department of Biochemistry and Molecular GeneticsAmerican University of BeirutBeirutLebanon; Department of GeneticsHarvard Medical School and Department of Internal MedicineMassachusetts General HospitalBostonMassachusetts
| | - Ruby Khalaf
- Department of Biochemistry and Molecular Genetics American University of Beirut Beirut Lebanon
| | - Rony Salloum
- Department of Biochemistry and Molecular Genetics American University of Beirut Beirut Lebanon
| | - Rabih R Andary
- Department of Biochemistry and Molecular Genetics American University of Beirut Beirut Lebanon
| | - Raya Safa
- Department of Biochemistry and Molecular Genetics American University of Beirut Beirut Lebanon
| | - Inaam El-Rassy
- Department of Biochemistry and Molecular Genetics American University of Beirut Beirut Lebanon
| | - Elie Moubarak
- National LDL Apheresis Center Dahr El-Bashek Governmental University Hospital Roumieh Lebanon
| | - Sami T Azar
- Department of Internal Medicine American University of Beirut Beirut Lebanon
| | - Fadi F Bitar
- Department of Pediatrics and Adolescent Medicine American University of Beirut Beirut Lebanon
| | - Georges Nemer
- Department of Biochemistry and Molecular Genetics American University of Beirut Beirut Lebanon
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8
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Update on the molecular biology of dyslipidemias. Clin Chim Acta 2016; 454:143-85. [DOI: 10.1016/j.cca.2015.10.033] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/24/2015] [Accepted: 10/30/2015] [Indexed: 12/20/2022]
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9
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Brautbar A, Leary E, Rasmussen K, Wilson DP, Steiner RD, Virani S. Genetics of familial hypercholesterolemia. Curr Atheroscler Rep 2015; 17:491. [PMID: 25712136 DOI: 10.1007/s11883-015-0491-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Familial hypercholesterolemia (FH) is a genetic disorder characterized by elevated low-density lipoprotein (LDL) cholesterol and premature cardiovascular disease, with a prevalence of approximately 1 in 200-500 for heterozygotes in North America and Europe. Monogenic FH is largely attributed to mutations in the LDLR, APOB, and PCSK9 genes. Differential diagnosis is critical to distinguish FH from conditions with phenotypically similar presentations to ensure appropriate therapeutic management and genetic counseling. Accurate diagnosis requires careful phenotyping based on clinical and biochemical presentation, validated by genetic testing. Recent investigations to discover additional genetic loci associated with extreme hypercholesterolemia using known FH families and population studies have met with limited success. Here, we provide a brief overview of the genetic determinants, differential diagnosis, genetic testing, and counseling of FH genetics.
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Affiliation(s)
- Ariel Brautbar
- Division of Genetics, Cook Children's Medical Center, Fort Worth, TX, USA,
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10
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Kulkarni H, Kos MZ, Neary J, Dyer TD, Kent JW, Göring HHH, Cole SA, Comuzzie AG, Almasy L, Mahaney MC, Curran JE, Blangero J, Carless MA. Novel epigenetic determinants of type 2 diabetes in Mexican-American families. Hum Mol Genet 2015; 24:5330-44. [PMID: 26101197 DOI: 10.1093/hmg/ddv232] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Accepted: 06/16/2015] [Indexed: 12/25/2022] Open
Abstract
Although DNA methylation is now recognized as an important mediator of complex diseases, the extent to which the genetic basis of such diseases is accounted for by DNA methylation is unknown. In the setting of large, extended families representing a minority, high-risk population of the USA, we aimed to characterize the role of epigenome-wide DNA methylation in type 2 diabetes (T2D). Using Illumina HumanMethylation450 BeadChip arrays, we tested for association of DNA methylation at 446 356 sites with age, sex and phenotypic traits related to T2D in 850 pedigreed Mexican-American individuals. Robust statistical analyses showed that (i) 15% of the methylome is significantly heritable, with a median heritability of 0.14; (ii) DNA methylation at 14% of CpG sites is associated with nearby sequence variants; (iii) 22% and 3% of the autosomal CpG sites are associated with age and sex, respectively; (iv) 53 CpG sites were significantly associated with liability to T2D, fasting blood glucose and insulin resistance; (v) DNA methylation levels at five CpG sites, mapping to three well-characterized genes (TXNIP, ABCG1 and SAMD12) independently explained 7.8% of the heritability of T2D (vi) methylation at these five sites was unlikely to be influenced by neighboring DNA sequence variation. Our study has identified novel epigenetic indicators of T2D risk in Mexican Americans who have increased risk for this disease. These results provide new insights into potential treatment targets of T2D.
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Affiliation(s)
- Hemant Kulkarni
- South Texas Diabetes and Obesity Institute, University of Texas Health Sciences Center at San Antonio, Regional Academic Health Center, Harlingen, TX 78550, USA and
| | - Mark Z Kos
- South Texas Diabetes and Obesity Institute, University of Texas Health Sciences Center at San Antonio, Regional Academic Health Center, Harlingen, TX 78550, USA and
| | - Jennifer Neary
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Thomas D Dyer
- South Texas Diabetes and Obesity Institute, University of Texas Health Sciences Center at San Antonio, Regional Academic Health Center, Harlingen, TX 78550, USA and
| | - Jack W Kent
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Harald H H Göring
- South Texas Diabetes and Obesity Institute, University of Texas Health Sciences Center at San Antonio, Regional Academic Health Center, Harlingen, TX 78550, USA and
| | - Shelley A Cole
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Anthony G Comuzzie
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Laura Almasy
- South Texas Diabetes and Obesity Institute, University of Texas Health Sciences Center at San Antonio, Regional Academic Health Center, Harlingen, TX 78550, USA and
| | - Michael C Mahaney
- South Texas Diabetes and Obesity Institute, University of Texas Health Sciences Center at San Antonio, Regional Academic Health Center, Harlingen, TX 78550, USA and
| | - Joanne E Curran
- South Texas Diabetes and Obesity Institute, University of Texas Health Sciences Center at San Antonio, Regional Academic Health Center, Harlingen, TX 78550, USA and
| | - John Blangero
- South Texas Diabetes and Obesity Institute, University of Texas Health Sciences Center at San Antonio, Regional Academic Health Center, Harlingen, TX 78550, USA and
| | - Melanie A Carless
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
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11
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Postmortem Examinations for the Etiological Identification of Juvenile Coronary Arteriosclerosis. Am J Forensic Med Pathol 2015; 36:149-52. [PMID: 26079403 DOI: 10.1097/paf.0000000000000171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The postmortem of suddenly deceased younger adults sometimes reveals that they experienced manifest coronary arteriosclerosis. We looked at 21 cases where stenosis of the coronary arteries was at least 50%. We supplemented our postmortem findings and the results from the postmortem identification of the lipid metabolism parameters with anamnestic details. We also conducted a genetic analysis. The risk factors such as smoking and family history were relatively frequent. In most of our cases, the postmortems showed significantly deviating lipid metabolism parameters. Compared to these findings, the genetic analyses only showed a clearly increased presence of APOE genotypes 3/4, whereas we observed no abnormalities in relation to the LDL receptor. The study results illustrate the multifactor genesis of premature coronary arteriosclerosis. Despite these limitations, the unexpected finding of juvenile coronary arteriosclerosis should entail an effort to establish the individual risk factors involved as this can provide vital information for medically advising other members of the family on their hereditary risks.
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12
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Li H, Zhang Y, Wei X, Peng Y, Yang P, Tan H, Chen C, Pan Q, Liang D, Wu L. Rare intracranial cholesterol deposition and a homozygous mutation of LDLR in a familial hypercholesterolemia patient. Gene 2015; 569:313-7. [PMID: 25936346 DOI: 10.1016/j.gene.2015.04.071] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 04/18/2015] [Accepted: 04/25/2015] [Indexed: 12/12/2022]
Abstract
Familial hypercholesterolemia (FH MIM# 143890) is one of the most common autosomal inherited diseases. FH is characterized by elevated plasma levels of total cholesterol and low-density lipoprotein-cholesterol. Mutation in the LDLR gene, which encodes the LDL receptor protein, is responsible for most of the morbidity of FH. The incidence of heterozygous FH is about 1/500, whereas the incidence of homozygous FH is only 1/1,000,000 in Caucasian population. In this study, we report a homozygous LDLR mutation (c.298G>A) in a familial hypercholesterolemia patient, who exhibited intracranial cholesterol deposition, which is a rare addition to the common FH phenotypes. The proband's consanguineous parents have the same heterozygous mutation with elevated concentrations of LDL-C but no xanthoma.
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Affiliation(s)
- Haoxian Li
- State Key Laboratory of Medical Genetics, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China
| | - Yanghui Zhang
- State Key Laboratory of Medical Genetics, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China
| | - Xianda Wei
- State Key Laboratory of Medical Genetics, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China
| | - Ying Peng
- State Key Laboratory of Medical Genetics, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China
| | - Pu Yang
- State Key Laboratory of Medical Genetics, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China
| | - Hu Tan
- State Key Laboratory of Medical Genetics, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China
| | - Chen Chen
- State Key Laboratory of Medical Genetics, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China
| | - Qian Pan
- State Key Laboratory of Medical Genetics, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China
| | - Desheng Liang
- State Key Laboratory of Medical Genetics, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China; Hunan Jiahui Genetics Hospital, 110 Xiangya Road, Changsha, Hunan 410078, China.
| | - Lingqian Wu
- State Key Laboratory of Medical Genetics, Central South University, 110 Xiangya Road, Changsha, Hunan 410078, China; Hunan Jiahui Genetics Hospital, 110 Xiangya Road, Changsha, Hunan 410078, China.
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13
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Novel mutations of low-density lipoprotein receptor gene in China patients with familial hypercholesterolemia. Appl Biochem Biotechnol 2015; 176:101-9. [PMID: 25846081 DOI: 10.1007/s12010-015-1554-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 02/22/2015] [Indexed: 12/30/2022]
Abstract
Familial hypercholesterolaemia (FH) is an autosomal dominant genetic disorder, associated with elevated level of serum low-density lipoprotein-cholesterol (LDL-C), which can lead to premature cardiovascular disease (CVD). Mutations in low density lipoprotein receptor (LDLR) and proprotein convertase subtilisin/kexin type 9 (PCSK9) have been identified to be the underlying cause of this disease. Genetic research of FH has already been extensively studied all over the world. However, reports of FH mutations in the Chinese population are still limited. In this paper, 20 unrelated FH families were enrolled to detect the candidate gene variants in Chinese FH population by DNA direct sequencing. We identified 12 LDLR variants in 13 FH probands. Importantly, we first reported two unique mutations (c.2000_2000 delG/p.C667LfsX6 and c.605T>C/p.F202S) in LDLR gene. Our discoveries expand the spectrum of LDLR mutations and contribute to the genetic diagnosis and counseling for FH patients.
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Fellin R, Arca M, Zuliani G, Calandra S, Bertolini S. The history of Autosomal Recessive Hypercholesterolemia (ARH). From clinical observations to gene identification. Gene 2015; 555:23-32. [PMID: 25225128 DOI: 10.1016/j.gene.2014.09.020] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 08/01/2014] [Accepted: 09/09/2014] [Indexed: 11/22/2022]
Abstract
The most frequent form of monogenic hypercholesterolemia, also known as Familial Hypercholesterolemia (FH), is characterized by plasma accumulation of cholesterol transported in Low Density Lipoproteins (LDLs). FH has a co-dominant transmission with a gene-dosage effect. FH heterozygotes have levels of plasma LDL-cholesterol (LDL-C) twice normal and present xanthomas and coronary heart disease (CHD) in adulthood. In rare FH homozygotes plasma LDL-C level is four times normal, while xanthomas and CHD are present from infancy. Most FH patients are carriers of mutations of the LDL receptor (LDLR); a minority of them carry either mutations in the Apolipoprotein B (ApoB), the protein constituent of LDLs which is the ligand for LDLR, or gain of function mutations of PCSK9, the protein responsible for the intracellular degradation of the LDLR. From 1970 to the mid 90s some publications described children with the clinical features of homozygous FH, who were born from normocholesterolemic parents, strongly suggesting a recessive transmission of FH. In these patients the involvement of LDLR and APOB genes was excluded. Interestingly, several patients were identified in the island of Sardinia (Italy), whose population has a peculiar genetic background due to geographical isolation. In this review, starting from the early descriptions of patients with putative recessive hypercholesterolemia, we highlight the milestones that led to the identification of a novel gene involved in LDL metabolism and the characterization of its encoded protein. The latter turned out to be an adaptor protein required for the LDLR-mediated endocytosis of LDLs in hepatocytes. The loss of function of this protein is the cause of Autosomal Recessive Hypercholesterolemia (ARH).
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Affiliation(s)
- Renato Fellin
- Department of Clinical & Experimental Medicine, Section of Internal Medicine, Gerontology & Nutrition, University of Ferrara, Via A. Moro, 8, I-44124 Ferrara, Italy
| | - Marcello Arca
- Department of Internal Medicine and Allied Sciences, Atherosclerosis Center, Sapienza University of Rome, Policlinico Umberto I, Viale del Policlinico, 00161 Rome, Italy
| | - Giovanni Zuliani
- Department of Clinical & Experimental Medicine, Section of Internal Medicine, Gerontology & Nutrition, University of Ferrara, Via A. Moro, 8, I-44124 Ferrara, Italy
| | - Sebastiano Calandra
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena & Reggio Emilia, Via Campi 287, I-41125 Modena, Italy.
| | - Stefano Bertolini
- Department of Internal Medicine, University of Genova, Viale Bendetto XV, I-16132 Genova, Italy
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Sirtori CR, Pavanello C, Bertolini S. Microsomal transfer protein (MTP) inhibition-a novel approach to the treatment of homozygous hypercholesterolemia. Ann Med 2014; 46:464-74. [PMID: 24987866 DOI: 10.3109/07853890.2014.931100] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Homozygous familial hypercholesterolemia (HoFH) represents the most severe lipoprotein disorder, generally attributable to mutation(s) of the low-density lipoprotein receptor (LDL-R), i.e. autosomal dominant hypercholesterolemia type 1 (ADH1). Much lower percentages are due to alterations of apolipoprotein B (ADH2), or gain-of-function mutations of proprotein convertase subtilisin/kexin type 9 (PCSK9) (ADH3). In certain geographical areas a significant number of patients may be affected by an autosomal recessive hypercholesterolemia (ARH). Mutations may be also combined (two mutations of the same gene, compound heterozygosity), or two in different genes (double heterozygosity). Among the most innovative therapeutic approaches made available recently, inhibitors of the microsomal transfer protein (MTP) system have shown a high clinical potential. MTP plays a critical role in the assembly/secretion of very-low-density lipoproteins (VLDL), and its absence leads to apo B deficiency. MTP antagonists dramatically lower LDL-cholesterol (LDL-C) in animals, although a reported increase of liver fat delayed their clinical development. Lomitapide, the best-studied MTP inhibitor, reduces LDL-C by 50% or more in HoFH patients, with modest, reversible, liver steatosis. Recent US approval has confirmed an acceptable tolerability, provided patients adhere to a strictly low-fat regimen. There are no clinical data on atherosclerosis reduction/regression, but animal models provide encouraging results.
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Sturm AC. The Role of Genetic Counselors for Patients with Familial Hypercholesterolemia. CURRENT GENETIC MEDICINE REPORTS 2014. [DOI: 10.1007/s40142-014-0036-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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