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Calling and Phasing of Single-Nucleotide and Structural Variants of the LDLR Gene Using Oxford Nanopore MinION. Int J Mol Sci 2023; 24:ijms24054471. [PMID: 36901902 PMCID: PMC10003201 DOI: 10.3390/ijms24054471] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/27/2023] [Accepted: 02/22/2023] [Indexed: 03/12/2023] Open
Abstract
The LDLR locus has clinical significance for lipid metabolism, Mendelian familial hypercholesterolemia (FH), and common lipid metabolism-related diseases (coronary artery disease and Alzheimer's disease), but its intronic and structural variants are underinvestigated. The aim of this study was to design and validate a method for nearly complete sequencing of the LDLR gene using long-read Oxford Nanopore sequencing technology (ONT). Five PCR amplicons from LDLR of three patients with compound heterozygous FH were analyzed. We used standard workflows of EPI2ME Labs for variant calling. All rare missense and small deletion variants detected previously by massively parallel sequencing and Sanger sequencing were identified using ONT. One patient had a 6976 bp deletion (exons 15 and 16) that was detected by ONT with precisely located breakpoints between AluY and AluSx1. Trans-heterozygous associations between mutation c.530C>T and c.1054T>C, c.2141-966_2390-330del, and c.1327T>C, and between mutations c.1246C>T and c.940+3_940+6del of LDLR, were confirmed. We demonstrated the ability of ONT to phase variants, thereby enabling haplotype assignment for LDLR with personalized resolution. The ONT-based method was able to detect exonic variants with the additional benefit of intronic analysis in one run. This method can serve as an efficient and cost-effective tool for diagnosing FH and conducting research on extended LDLR haplotype reconstruction.
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2
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Barbosa TKA, Hirata RDC, Ferreira GM, Borges JB, Oliveira VFD, Gorjão R, Marçal ERDS, Gonçalves RM, Faludi AA, Freitas RCCD, Dagli-Hernandez C, Bortolin RH, Bastos GM, Pithon-Curi TC, Nader HB, Hirata MH. LDLR missense variants disturb structural conformation and LDLR activity in T-lymphocytes of Familial hypercholesterolemia patients. Gene X 2023; 853:147084. [PMID: 36464169 DOI: 10.1016/j.gene.2022.147084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/16/2022] [Accepted: 11/28/2022] [Indexed: 12/05/2022] Open
Abstract
Familial hypercholesterolemia (FH) is caused by deleterious mutations in the LDLR that increase markedly low-density lipoprotein (LDL) cholesterol and cause premature atherosclerotic cardiovascular disease. Functional effects of pathogenic LDLR variants identified in Brazilian FH patients were assessed using in vitro and in silico studies. Variants in LDLR and other FH-related genes were detected by exon-target gene sequencing. T-lymphocytes were isolated from 26 FH patients, and 3 healthy controls and LDLR expression and activity were assessed by flow cytometry and confocal microscopy. The impact of LDLR missense variants on protein structure was assessed by molecular modeling analysis. Ten pathogenic or likely pathogenic LDLR variants (six missense, two stop-gain, one frameshift, and one in splicing region) and six non-pathogenic variants were identified. Carriers of pathogenic and non-pathogenic variants had lower LDL binding and uptake in activated T-lymphocytes compared to controls (p < 0.05), but these variants did not influence LDLR expression on cell surface. Reduced LDL binding and uptake was also observed in carriers of LDLR null and defective variants. Modeling analysis showed that p.(Ala431Thr), p.(Gly549Asp) and p.(Gly592Glu) disturb intramolecular interactions of LDLR, and p.(Gly373Asp) and p.(Ile488Thr) reduce the stability of the LDLR protein. Docking and molecular interactions analyses showed that p.(Cys184Tyr) and p.(Gly373Asp) alter interaction of LDLR with Apolipoprotein B (ApoB). In conclusion, LDLR null and defective variants reduce LDL binding capacity and uptake in activated T-lymphocytes of FH patients and LDLR missense variants affect LDLR conformational stability and dissociation of the LDLR-ApoB complex, having a potential role in FH pathogenesis.
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Affiliation(s)
- Thais Kristini Almendros Barbosa
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo 05508-000, Brazil
| | - Rosario Dominguez Crespo Hirata
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo 05508-000, Brazil
| | - Glaucio Monteiro Ferreira
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo 05508-000, Brazil; Laboratory of Molecular Research in Cardiology, Institute Dante Pazzanese of Cardiology, Sao Paulo 04012-909, Brazil
| | - Jéssica Bassani Borges
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo 05508-000, Brazil; Laboratory of Molecular Research in Cardiology, Institute Dante Pazzanese of Cardiology, Sao Paulo 04012-909, Brazil
| | - Victor Fernandes de Oliveira
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo 05508-000, Brazil
| | - Renata Gorjão
- Interdisciplinary Post-graduate Program in Health Sciences, Cruzeiro do Sul University, Sao Paulo 01506-000, Brazil
| | - Elisangela Rodrigues da Silva Marçal
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo 05508-000, Brazil; Laboratory of Molecular Research in Cardiology, Institute Dante Pazzanese of Cardiology, Sao Paulo 04012-909, Brazil
| | | | - André Arpad Faludi
- Medical Clinic Division, Institute Dante Pazzanese of Cardiology, Sao Paulo 04012-909, Brazil
| | - Renata Caroline Costa de Freitas
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo 05508-000, Brazil; Department of Cardiac Surgery, Boston Children's Hospital, Boston, MA 02115, United States
| | - Carolina Dagli-Hernandez
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo 05508-000, Brazil
| | - Raul Hernandes Bortolin
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo 05508-000, Brazil; Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, United States
| | - Gisele Medeiros Bastos
- Laboratory of Molecular Research in Cardiology, Institute Dante Pazzanese of Cardiology, Sao Paulo 04012-909, Brazil; Department of Teaching and Research, Real e Benemerita Associaçao Portuguesa de Beneficiencia, Sao Paulo 01323-001, Brazil
| | - Tania Cristina Pithon-Curi
- Interdisciplinary Post-graduate Program in Health Sciences, Cruzeiro do Sul University, Sao Paulo 01506-000, Brazil
| | - Helena Bonciani Nader
- Department of Biochemistry, School of Medicine, Federal University of Sao Paulo, Sao Paulo 04044-020, Brazil
| | - Mario Hiroyuki Hirata
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo 05508-000, Brazil.
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Sánchez-Hernández RM, Civeira F, Stef M, Perez-Calahorra S, Almagro F, Plana N, Novoa FJ, Sáenz-Aranzubía P, Mosquera D, Soler C, Fuentes FJ, Brito-Casillas Y, Real JT, Blanco-Vaca F, Ascaso JF, Pocovi M. Homozygous Familial Hypercholesterolemia in Spain. ACTA ACUST UNITED AC 2016; 9:504-510. [DOI: 10.1161/circgenetics.116.001545] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 09/28/2016] [Indexed: 11/16/2022]
Abstract
Background—
Homozygous familial hypercholesterolemia (HoFH) is a rare disease characterized by elevated plasma levels of low-density lipoprotein cholesterol (LDL-C) and extremely high risk of premature atherosclerotic cardiovascular disease. HoFH is caused by mutations in several genes, including LDL receptor (
LDLR
), apolipoprotein B (
APOB
), proprotein convertase subtilisin/kexin type 9 (
PCSK9
), and LDL protein receptor adaptor 1 (
LDLRAP1
). No epidemiological studies have assessed HoFH prevalence or the clinical and molecular characteristics of this condition. Here, we aimed to characterize HoFH in Spain.
Methods and Results—
Data were collected from the Spanish Dyslipidemia Registry of the Spanish Atherosclerosis Society and from all molecular diagnoses performed for familial hypercholesterolemia in Spain between 1996 and 2015 (n=16 751). Clinical data included baseline lipid levels and atherosclerotic cardiovascular disease events. A total of 97 subjects were identified as having HoFH—of whom, 47 were true homozygous (1 for
APOB
, 5 for
LDLRAP1
, and 41 for
LDLR
), 45 compound heterozygous for
LDLR
, 3 double heterozygous for
LDLR
and
PSCK9
, and 2 double heterozygous for
LDLR
and
APOB
. No
PSCK9
homozygous cases were identified. Two variants in
LDLR
were identified in 4.8% of the molecular studies. Over 50% of patients did not meet the classical HoFH diagnosis criteria. The estimated HoFH prevalence was 1:450 000. Compared with compound heterozygous cases, true homozygous cases showed more aggressive phenotypes with higher LDL-C and more atherosclerotic cardiovascular disease events.
Conclusions—
HoFH frequency in Spain was higher than expected. Clinical criteria would underestimate the actual prevalence of individuals with genetic HoFH, highlighting the importance of genetic analysis to improve familial hypercholesterolemia diagnosis accuracy.
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Eroglu Z, Harman E, Vardarli E, Kayikcioglu M, Vardarli AT. LDLR C1725T Gene Polymorphism Frequency in Type 2 Diabetes Mellitus Patients With Dyslipidemia. J Clin Med Res 2016; 8:793-796. [PMID: 27738480 PMCID: PMC5047017 DOI: 10.14740/jocmr2739w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2016] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Dyslipidemia has a substantial role in the development of cardiovascular diseases in patients with type 2 diabetes mellitus (T2DM). Determining the genetic profile of T2DM patients with dyslipidemia is important in order to reduce the risk of microvascular and macrovascular complications. Low-density lipoprotein receptor (LDLR) plays a critical role in plasma lipoprotein hemostasis. LDLR mutations/polymorphisms cause changes at the lipoprotein level. The objective of this study is to determine the frequency of LDLR (rs179989) polymorphisms in Turkish T2DM patients with dyslipidemia. METHODS The study group consisted of 217 T2DM patients with dyslipidemia including 28 cases with myocardial infarction and 212 healthy controls. Genomic DNA was isolated from venous blood samples and genotype analysis was carried out on the LightCycler® 480 instrument. The χ2 test was used to compare genotype distributions. RESULTS There were no significant differences in the frequency or allelic distribution of the LDLR C1725T (rs1799898) genotype between the type 2 diabetic dyslipidemia patients and the control group (P > 0.05). CONCLUSION LDLR C1725T polymorphism was not associated with lipid parameters, and dyslipidemia in T2DM patients.
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Affiliation(s)
- Zuhal Eroglu
- Department of Medical Biology, Medicine Faculty, Ege University, Izmir, Turkey
| | - Ece Harman
- Division of Endocrinology and Metabolism Disease, Department of Internal Medicine, Medical Faculty, Katip Celebi University, Izmir, Turkey
| | | | - Meral Kayikcioglu
- Department of Cardiology, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Asli Tetik Vardarli
- Department of Medical Biology, Medicine Faculty, Ege University, Izmir, Turkey
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Palacios L, Grandoso L, Cuevas N, Olano-Martín E, Martinez A, Tejedor D, Stef M. Molecular characterization of familial hypercholesterolemia in Spain. Atherosclerosis 2011; 221:137-42. [PMID: 22244043 DOI: 10.1016/j.atherosclerosis.2011.12.021] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 11/25/2011] [Accepted: 12/16/2011] [Indexed: 11/29/2022]
Abstract
Familial hypercholesterolemia (FH), characterized by isolated elevation of plasmatic low-density lipoprotein (LDL) cholesterol and premature coronary heart disease (CHD), is associated with mutations in three major genes: LDL receptor (LDLR), apolipoprotein B (APOB) and proprotein convertase subtilisin/kexin 9 (PCSK9). We have analyzed 5430 Spanish index cases and 2223 relatives since 2004 with LIPOchip(®) genetic diagnostic platform, a microarray for the detection of Spanish common mutations in these three genes, including copy number variation (CNV) in LDLR, followed by sequencing analysis of the coding regions of LDLR and exon 26 of APOB, when the result is negative. Samples were received from hospitals of all around Spain. The preferred clinical criterion to diagnose FH was Dutch Lipid Clinic Network (DLCN) score. Our results show that there is a broad spectrum of mutations in the LDLR gene in Spain since about 400 different mutations were detected, distributed along almost the whole LDLR gene. Mutations in APOB (mainly p.Arg3527Gln) covered 6.5% of positive cases and only one PCSK9 mutation was detected. We found correlation between more severe mutations and the clinical diagnosis but also that 28% of FH patients harboring mutations do not have a definite clinical diagnosis. This study analyzes the mutation spectrum in Spain, remarks the importance of genetic diagnosis of FH patients, as well as the cascade screening, and shows how it is being carried out in Spain.
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