3259Next-generation sequencing to confirm clinical FH in The Netherlands

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
L Reeskamp ◽  
L C Zuurbier ◽  
G K Hovingh ◽  
J C Defesche
Keyword(s):  
The Netherlands ◽  
Low Density Lipoprotein ◽  
Genetic Defect ◽  
Copy Number Variants ◽  
Density Lipoprotein ◽  
Molecular Testing ◽  
Targeted Next Generation Sequencing ◽  
Lipid Clinic ◽  
Pathogenic Variants ◽  
Generation Sequencing

Abstract Background Pathogenic variants in the genes encoding the low-density lipoprotein receptor (LDLR), apolipoprotein B100 (APOB) and proprotein convertase subtilisin/kexin type 9 (PCSK9)) are known to cause familial hypercholesterolemia (FH), a disease characterized by high LDL-C levels. We set out to investigate which proportion of patients with extremely elevated LDL-C levels, who were referred for molecular analysis, carry a mutation in any of the three FH genes or other, putative FH genes. Methods Targeted next-generation sequencing of 28 genes involved in lipid metabolism was performed in 1475 clinical FH patients with LDL-C levels >5mmol/L (corresponding with possible, probable and definite FH score according to the Dutch Lipid Clinic Network criteria) and triglyceride levels <4.5 mmol/L. Genetic variants and copy number variants were curated consecutively using specialist analysis software. (Likely) pathogenic variants in LDLR, APOB, or PCSK9 were annotated as FH-causing variants. Results 14.3% of the 1475 patients with clinical FH were heterozygous carriers of a mutation in LDLR, APOB, or PCSK9. This number ranged from 8% in the lowest LDL-C group (5–5.99 mmol/L) to 56% in patients with the highest LDL-C levels (>8 mmol/L). Patients with LDLR, APOB, or PCSK9 variants had median LDL-C levels of 6.8 [5.7–7.9], 6.2 [5.1–7.0], and 6.4 [5.7–6.8] mmol/L [interquartile range], respectively. Mutation-negative FH patients had median LDL-C levels of 5.8 [5.2–6.5] mmol/L. Of the FH mutation-negative patients 7.4% had a (likely) pathogenic variant in the gene encoding lipoprotein lipase (LPL) and 1.3% in the apolipoprotein E (APOE) gene. The proportion of FH mutation-negative patients carrying an APOE variant increased from 1.2% in the lowest LDL-C group to 7.5% in patients with LDL-C >8 mmol/L. Mutation-positive FH patients were significantly younger (41.61±17.53 years vs 52.62±13.28 years P<0.001) and had a significant lower BMI (25.86±4.87 vs 26.55±4.07kg/m2, P=0.02) compared to mutation negative patients. Figure 1 Conclusions A genetic defect in LDLR, APOB or PCSK9 is identified in only 14.3% of the patients with a clinical FH phenotype (defined as LDL-C >5 mmol/L) referred for molecular testing in the Netherlands. Mutations in LPL and APOE were found in a minor proportion of the FH mutation-negative patients. Our finding that a mutation is only found 56% of patients who present with LDL-C levels above 8 mmol/L indicates that either misclassification of FH and/or other genetic defects may be present in this group. Acknowledgement/Funding Grant [016.156.445] from The Netherlands Organisation for Scientific Research (NWO)

Abstract 435: An Electronic Health Records Query for Severe Hypercholesterolemia Identifies Individuals With Undiagnosed Clinical and Molecular FH at a Tertiary Academic Centre

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Ezim Ajufo ◽  
Masako Ueda ◽  
Tracey Sikora ◽  
Emil M deGoma ◽  
Kristen Dilzell ◽  
...  
Keyword(s):  
In Silico ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
University Of Pennsylvania ◽  
High Yield ◽  
Heterozygous Mutation ◽  
Molecular Testing ◽  
Variants Of Unknown Significance ◽  
Lipid Clinic ◽  
Heritable Disorder

Background: Familial hypercholesterolemia (FH) is a common heritable disorder of elevated low density lipoprotein cholesterol (LDL-C) with an estimated prevalence of 1/200-300 in the US; however, fewer than 10% of cases have been identified. We wanted to examine whether a simple EHR query for severe hypercholesterolemia could be used to identify clinically and genetically defined cases of FH. Objectives/Purpose: We tested the hypothesis that querying the EHR using an LDL-C criterion would be a novel way to screen for and ultimately identify undiagnosed cases of FH. Methods: An EHR screening query was used to identify active adult patients with LDL-C ≥ 220 mg/dL in the University of Pennsylvania outpatient EHR database. Patients with secondary causes of hypercholesterolemia and those who had previous genetic testing for FH were excluded. The query identified 3,475 individuals, 120 were subsequently consented and enrolled for molecular testing. This was performed with next-generation sequencing using Progenika’s SEQPRO LIPO IS platform, targeting LDLR, APOB, PCSK9 and LDLRAP1 . A literature search was performed to gather information on identified LDLR variants of unknown significance (VUS). In addition, in-silico analysis was employed to evaluate the pathogenicity of the LDLR and LDLRAP1 VUS. Results: Among the 120 subjects, 53 (44.2%) met the Dutch Lipid Clinic Network (DLCN) criteria for probable or definite clinical FH. Molecularly, 19 FH-related pathogenic mutations were found in 18 (15%) individuals. Four had a common APOB ( R3500Q) mutation, 14 had a LDLR mutation. One individual had a double heterozygous mutation in PCSK9 and LDLR. In addition, 17 LDLR VUS were identified in 16 (13.9%) individuals. A literature review and in-silico analysis predicted that 8 VUS found in 10 subjects were “disease causing”. Therefore, a total of 28 (24.3%) subjects from our cohort carried either a FH causal mutation or likely pathogenic variant. Overall, 59 subjects (49.2%) in our cohort were ascertained to have either a clinical or molecular diagnosis of FH. Conclusion: The use of an EHR screening query for severe hypercholesterolemia was a novel, low investment but relatively high yield approach for identifying undiagnosed cases of FH at a tertiary academic centre.

scholarly journals Genetic basis of hypercholesterolemia in adults

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Seyedmohammad Saadatagah ◽  
Merin Jose ◽  
Ozan Dikilitas ◽  
Lubna Alhabi ◽  
Alexandra A. Miller ◽  
...  
Keyword(s):  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Population Based ◽  
Single Nucleotide Variants ◽  
Genetic Etiology ◽  
Single Nucleotide ◽  
Primary Hypercholesterolemia ◽  
Clinical Criteria ◽  
Lipid Clinic ◽  
Pathogenic Variants

AbstractWe investigated monogenic and polygenic causes of hypercholesterolemia in a population-based cohort, excluding secondary hypercholesterolemia, and using an established framework to identify pathogenic variants. We studied 1682 individuals (50.2 ± 8.6 years, 41.3% males) from southeast Minnesota with primary hypercholesterolemia (low-density lipoprotein cholesterol (LDL-C) ≥155 mg/dl in the absence of identifiable secondary causes). Familial hypercholesterolemia (FH) phenotype was defined as a Dutch Lipid Clinic Network (DLCN) score ≥6. Participants underwent sequencing of LDLR, APOB, and PCSK9, and genotyping of 12 LDL-C-associated single-nucleotide variants to construct a polygenic score (PGS) for LDL-C. The presence of a pathogenic/likely pathogenic variant was considered monogenic etiology and a PGS ≥90th percentile was considered polygenic etiology. The mean LDL-C level was 187.3 ± 32.3 mg/dl and phenotypic FH was present in 8.4% of the cohort. An identifiable genetic etiology was present in 17.1% individuals (monogenic in 1.5% and polygenic in 15.6%). Phenotypic and genetic FH showed poor overlap. Only 26% of those who met the clinical criteria of FH had an identifiable genetic etiology and of those with an identifiable genetic etiology only 12.9% met clinical criteria for FH. Genetic factors explained 7.4% of the variance in LDL-C. In conclusion, in adults with primary hypercholesterolemia, 17.1% had an identifiable genetic etiology and the overlap between phenotypic and genetic FH was modest.

scholarly journals Improving Familial Hypercholesterolemia Index Case Detection: Sequential Active Screening from Centralized Analytical Data

2021 ◽  
Vol 10 (4) ◽  
pp. 749
Author(s):  
Fernando Sabatel-Pérez ◽  
Joaquín Sánchez-Prieto ◽  
Víctor Manuel Becerra-Muñoz ◽  
Juan Horacio Alonso-Briales ◽  
Pedro Mata ◽  
...  
Keyword(s):  
Familial Hypercholesterolemia ◽  
Diagnostic Yield ◽  
Low Density Lipoprotein ◽  
Analytical Data ◽  
Genetic Diagnosis ◽  
Density Lipoprotein ◽  
Screening Strategy ◽  
Cascade Screening ◽  
Active Screening ◽  
Lipid Clinic

The majority of familial hypercholesterolemia index cases (FH-IC) remain underdiagnosed and undertreated because there are no well-defined strategies for the universal detection of FH. The aim of this study was to evaluate the diagnostic yield of an active screening for FH-IC based on centralized analytical data. From 2016 to 2019, a clinical screening of FH was performed on 469 subjects with severe hypercholesterolemia (low-density lipoprotein cholesterol ≥220 mg/dL), applying the Dutch Lipid Clinic Network (DLCN) criteria. All patients with a DLCN ≥ 6 were genetically tested, as were 10 patients with a DLCN of 3–5 points to compare the diagnostic yield between the two groups. FH was genetically confirmed in 57 of the 84 patients with DLCN ≥ 6, with a genetic diagnosis rate of 67.9% and an overall prevalence of 12.2% (95% confidence interval: 9.3% to 15.5%). Before inclusion in the study, only 36.8% (n = 21) of the patients with the FH mutation had been clinically diagnosed with FH; after genetic screening, FH detection increased 2.3-fold (p < 0.001). The sequential, active screening strategy for FH-IC increases the diagnostic yield for FH with a rational use of the available resources, which may facilitate the implementation of FH universal and family-based cascade screening strategies.

scholarly journals Novel TTLL5 Variants Associated with Cone-Rod Dystrophy and Early-Onset Severe Retinal Dystrophy

2021 ◽  
Vol 22 (12) ◽  
pp. 6410
Author(s):  
Vasily Smirnov ◽  
Olivier Grunewald ◽  
Jean Muller ◽  
Christina Zeitz ◽  
Carolin D. Obermaier ◽  
...  
Keyword(s):  
Early Onset ◽  
Retinal Dystrophy ◽  
Copy Number Variants ◽  
Cone Dystrophy ◽  
The Novel ◽  
Targeted Next Generation Sequencing ◽  
Large Deletions ◽  
Gene Panels ◽  
Generation Sequencing

Variants of the TTLL5 gene, which encodes tubulin tyrosine ligase-like family member five, are a rare cause of cone dystrophy (COD) or cone-rod dystrophy (CORD). To date, only a few TTLL5 patients have been clinically and genetically described. In this study, we report five patients harbouring biallelic variants of TTLL5. Four adult patients presented either COD or CORD with onset in the late teenage years. The youngest patient had a phenotype of early onset severe retinal dystrophy (EOSRD). Genetic analysis was performed by targeted next generation sequencing of gene panels and assessment of copy number variants (CNV). We identified eight variants, of which six were novel, including two large multiexon deletions in patients with COD or CORD, while the EOSRD patient harboured the novel homozygous p.(Trp640*) variant and three distinct USH2A variants, which might explain the observed rod involvement. Our study highlights the role of TTLL5 in COD/CORD and the importance of large deletions. These findings suggest that COD or CORD patients lacking variants in known genes may harbour CNVs to be discovered in TTLL5, previously undetected by classical sequencing methods. In addition, variable phenotypes in TTLL5-associated patients might be due to the presence of additional gene defects.

Estimated Prevalence of Familial Hypercholesterolemia Among Egyptian Patients with Acute Coronary Syndromes; Analysis from The Cardiorisk Project

2021 ◽  
Vol 23 (Supplement_D) ◽  
Author(s):  
Ashraf Reda ◽  
Ahmed Bendary ◽  
Ahmed Shawky Elserafy ◽  
Elsayed Farag ◽  
Tamer Mostafa ◽  
...  
Keyword(s):  
Familial Hypercholesterolemia ◽  
Acute Coronary Syndromes ◽  
Total Population ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Cross Sectional ◽  
Lipid Clinic ◽  
Egyptian Patients ◽  
Coronary Syndromes ◽  
Premature Cad

Abstract Aims The prevalence of familial hypercholesterolemia (FH) in Egypt is largely un- known. We aimed to estimate the prevalence of FH among 3224 Egyptian patients with acute coronary syndromes enrolled from 2015 to 2018 in the nationwide cross- sectional cardioRisk project. Methods and Results We applied the Dutch Lipid Clinic criteria for the diagnosis of FH on the available data recorded for the patients enrolled in the CardioRisk project. Two main criteria were applied: the presence of premature CAD (given 2 points in the Dutch criteria), and the categorized low density lipoprotein cholesterol (LDL-C) lev- els (given 1, 3, 5, or 8 points in the Dutch criteria according to the level). From a total of 3224 patients, 2743 patients had available LDL-C levels. Among those patients, when applying the abovementioned 2 criteria, we estimated that 472 patients had at least ‘possible’ FH (17.2% of the total population). Specifically, 4 patients had ‘defi- nite’ FH (0.1%), 7 patients had ‘probable’ FH (0.25%), and 461 patients had ‘possi- ble’ FH (16.8%). Conclusion The estimated prevalence of at least ‘possible’ FH among Egyptian patients with ACS is 17%.

scholarly journals Monoclonal Antibodies in the Management of Familial Hypercholesterolemia: Focus on PCSK9 and ANGPTL3 Inhibitors

2021 ◽  
Vol 23 (12) ◽  
Author(s):  
Angela Pirillo ◽  
Alberico L. Catapano ◽  
Giuseppe D. Norata
Keyword(s):  
Monoclonal Antibodies ◽  
High Risk ◽  
Familial Hypercholesterolemia ◽  
Plasma Levels ◽  
Low Density Lipoprotein ◽  
Genetic Defect ◽  
Density Lipoprotein ◽  
Lipid Lowering ◽  
Low Density ◽  
Premature Cardiovascular Disease

Abstract Purpose of Review Familial hypercholesterolemia (FH) is a monogenic disorder characterized by high plasma levels of low-density lipoprotein cholesterol (LDL-C) since birth and a high risk of premature cardiovascular disease. The genetic defect is carried in only one allele in heterozygous FH (HeFH) or in both in the most severe homozygous FH (HoFH). Current guidelines recommend to reduce substantially LDL-C levels in these high-risk patients, with the need to use association therapy combining agents with different mechanisms of action. As most cases of FH are attributable to mutations in the gene encoding the low-density lipoprotein receptor (LDLR), statins, even in combination with ezetimibe, are less effective in reducing LDL-C plasma levels in FH patients, who require a more intensive approach with additional lipid-lowering agents. Additional targets playing key roles in regulating LDL-C levels are represented by PCSK9 and ANGPTL3. Recent Findings Two monoclonal antibodies (mAbs) targeting PCSK9, evolocumab and alirocumab, significantly reduce LDL-C levels in HeFH patients. In patients with HoFH, the efficacy of mAbs to PCSK9 is strictly related to the presence of a residual LDLR activity; thus, patients carrying null mutations do not respond to the therapy with these mAbs, whereas some effects can be appreciated in HoFH bearing defective mutations. Conversely, evinacumab, the mAb targeting ANGPTL3, is highly effective in reducing LDL-C levels even in HoFH patients carrying null LDLR mutations, thanks to its LDLR-independent mechanism of action. Summary Monoclonal antibodies inhibiting PCSK9 have shown a robust effect in FH patients presenting a residual LDLR activity, while ANGPTL3 inhibitors appear to be promising even in patients carrying null LDLR mutations.

Genetic Characterization of Hereditary Cancer Syndromes Based on Targeted Next-Generation Sequencing

2021 ◽  
pp. 1-9
Author(s):  
Pelin Ercoskun ◽  
Cigdem Yuce Kahraman ◽  
Guller Ozkan ◽  
Abdulgani Tatar
Keyword(s):  
Hereditary Cancer ◽  
Hereditary Cancer Syndrome ◽  
Cancer Syndrome ◽  
Targeted Next Generation Sequencing ◽  
Pathogenic Variants ◽  
Novel Variants ◽  
Genetics And Genomics ◽  
Cancer Syndromes ◽  
Generation Sequencing

A hereditary cancer syndrome is a genetic predisposition to cancer caused by a germline mutation in cancer-related genes. Identifying the disease-causing variant is important for both the patient and relatives at risk in cancer families because this could be a guide in treatment and secondary cancer prevention. In this study, hereditary cancer panel harboring cancer-related genes was performed on MiSeq Illumina NGS system from peripheral blood samples. Sequencing files were fed into a cloud-based data analysis pipeline. Reportable variants were classified according to the American College of Medical Genetics and Genomics guidelines. Three hundred five individuals were included in the study. Different pathogenic/likely pathogenic variants were detected in 75 individuals. The majority of these variants were in the <i>MUTYH</i>, <i>BRCA2</i>, and <i>CHEK2</i> genes. Nine novel pathogenic/likely pathogenic variants were identified in <i>BRCA1</i>, <i>BRCA2</i>, <i>GALNT12</i>, <i>ATM</i>, <i>MLH1</i>, <i>MSH2</i>, <i>APC</i>, and <i>KIT</i> genes. We obtained interesting and novel variants which could be related to hereditary cancer, and this study confirmed that NGS is an indispensable method for the risk assessment in cancer families.

Abstract 14681: Comparative Study Between International Guidelines in Detecting Pediatric Familial Hypercholesterolemia Through a Unique Community Health System in Kagawa, Japan

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Keiji Matsunaga ◽  
Asako Mizobuchi ◽  
Hayato Tada ◽  
Tsuyoshi Sasaki ◽  
Yoshihiro Asano ◽  
...  
Keyword(s):  
Health System ◽  
Community Health ◽  
Familial Hypercholesterolemia ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Hereditary Disease ◽  
International Guidelines ◽  
Number Of Children ◽  
Lipid Clinic ◽  
Lipid Screening

Introduction: Familial hypercholesterolemia (FH) is an autosomal hereditary disease found in patients who have elevated low-density lipoprotein cholesterol (LDL-C) from birth. Early detection and treatment of FH during childhood potentially reduces the risk of premature cardiovascular events. In Kagawa prefecture, a unique community health system, involving three steps, has been conducted to prevent lifestyle-related diseases for 10-year-old children. This system includes universal lipid screening, selection by pediatricians, and next-generation sequencing (NGS) of FH-related genes in hospitals. The aim of this study is to compare 3 international guidelines to detect pediatric FH with this unique community health system in Kagawa. Methods: In Kagawa prefecture, the universal lipid screening of approximately 8,000 children at 10 years of age is performed annually, covering over 90% of the target group. After excluding secondary hypercholesterolemia, pediatric clinics introduced children with LDL-C >140mg/dL to 4 designated hospitals to perform NGS. We applied the guidelines of the Dutch Lipid Clinic Network (DLCN), Simon Broome (SB), and the Japanese Atherosclerosis Society (JAS) to children who received NGS in the unique community health system in Kagawa. Results: We performed NGS for 46 children from January 2018 to February 2020 (LDL-C 186.0±50.3 mg/dL; Male/F 27/19) and 26 (57%) had FH genetic mutations (23 LDL-R and 3 PCSK9 mutations). Seventeen children met FH criteria for DLCN (35%), 10 for Simon Broome (22%), and 11 for JAS (24%), respectively. The combination of NGS and either of the 3 guidelines increased the number of children diagnosed as FH up to 31 (67%). Conclusion: International guidelines detected only half of pediatric FH who were diagnosed by the unique community health system in Kagawa. Further investigation will be required to build an effective universal screening system for pediatric FH.

Improved phenotyping of apolipoprotein E: application to population frequency distribution

1990 ◽  
Vol 36 (11) ◽  
pp. 1871-1874 ◽  
Author(s):  
J S Hill ◽  
P H Pritchard
Keyword(s):  
Population Studies ◽  
Clinical Laboratory ◽  
Simple Procedure ◽  
Low Density Lipoprotein ◽  
Large Population ◽  
Density Lipoprotein ◽  
Lipid Clinic ◽  
Apo E ◽  
Slab Gels ◽  
Peroxidase Conjugate

Abstract A simple procedure for phenotyping apolipoprotein (apo) E directly from plasma has been developed for use in the lipid clinic laboratory. In this new method, 10 microL of serum or plasma is pretreated with neuraminidase (EC 3.2.1.18), which removes the sialic acid residues from apo E and eliminates additional bands, thereby ensuring correct phenotype assignment. After a rapid delipidation step, the samples are focused in vertical polyacrylamide mini-slab gels and immunoblotted with a polyclonal goat anti-apo E antibody, followed by a Protein G-peroxidase conjugate. The accuracy of this method was confirmed by comparison with the established procedure of phenotyping by isoelectric focusing of delipidated very-low-density lipoprotein. In addition, sera from 203 subjects from Vancouver, selected without conscious bias, were used to determine the local distribution of the apo E alleles. We estimate that the relative frequencies of apo E alleles epsilon 2, epsilon 3, and epsilon 4 in this population are 0.086, 0.761, and 0.153, respectively. The speed and convenience of using minigels make this procedure ideal for clinical laboratory applications and large population studies.

Differences in phenotype, genotype and cardiovascular events between patients with probable and definite heterozygous familial hypercholesterolemia

2019 ◽  
Vol 16 (6) ◽  
pp. 467-478
Author(s):  
Ye-Xuan Cao ◽  
Bing-Yang Zhou ◽  
Di Sun ◽  
Sha Li ◽  
Yuan-Lin Guo ◽  
...  
Keyword(s):  
Familial Hypercholesterolemia ◽  
Cardiovascular Events ◽  
Oxidized Ldl ◽  
Low Density Lipoprotein ◽  
Survival Rates ◽  
Gene Mutations ◽  
Density Lipoprotein ◽  
Heterozygous Familial Hypercholesterolemia ◽  
Lipid Clinic ◽  
Kaplan Meier

Aim: To investigated the potential differences between probable and definite heterozygous familial hypercholesterolemia (HeFH) patients diagnosed by Dutch Lipid Clinic Network criteria. Methods: Clinical characteristics, lipid profile, severity of coronary artery stenosis and gene mutations were compared. Kaplan–Meier curve was performed to evaluate the cardiovascular events. Results: Overall, 325 participants were included and divided into two groups: probable (n = 233) and definite HeFH (n = 92). Definite HeFH patients had higher low-density lipoprotein cholesterol (LDL-C), oxidized-LDL and proprotein convertase subtilisin/kexin 9 levels, and higher prevalence of tendon xanthomas. The incidence of genetic mutations was statistically higher in definite HeFH than probable HeFH patients. The coronary stenosis calculated by Gensini score was statistically severer in definite HeFH patients. The best LDL-C threshold for predicting mutations was 5.14 mmol/l. Definite HeFH had lower event-free survival rates. Conclusion: Definite HeFH patients had higher severity of phenotype and genotype, and higher risk of cardiovascular events.

Sign in / Sign up

Export Citation Format

Share Document