Dataset Information

Diagnostic Yield and Clinical Utility of Sequencing Familial Hypercholesterolemia Genes in Patients With Severe Hypercholesterolemia.

ABSTRACT: BACKGROUND:Approximately 7% of American adults have severe hypercholesterolemia (untreated low-density lipoprotein [LDL] cholesterol ?190 mg/dl), which may be due to familial hypercholesterolemia (FH). Lifelong LDL cholesterol elevations in FH mutation carriers may confer coronary artery disease (CAD) risk beyond that captured by a single LDL cholesterol measurement. OBJECTIVES:This study assessed the prevalence of an FH mutation among those with severe hypercholesterolemia and determined whether CAD risk varies according to mutation status beyond the observed LDL cholesterol level. METHODS:Three genes causative for FH (LDLR, APOB, and PCSK9) were sequenced in 26,025 participants from 7 case-control studies (5,540 CAD case subjects, 8,577 CAD-free control subjects) and 5 prospective cohort studies (11,908 participants). FH mutations included loss-of-function variants in LDLR, missense mutations in LDLR predicted to be damaging, and variants linked to FH in ClinVar, a clinical genetics database. RESULTS:Among 20,485 CAD-free control and prospective cohort participants, 1,386 (6.7%) had LDL cholesterol ?190 mg/dl; of these, only 24 (1.7%) carried an FH mutation. Within any stratum of observed LDL cholesterol, risk of CAD was higher among FH mutation carriers than noncarriers. Compared with a reference group with LDL cholesterol <130 mg/dl and no mutation, participants with LDL cholesterol ?190 mg/dl and no FH mutation had a 6-fold higher risk for CAD (odds ratio: 6.0; 95% confidence interval: 5.2 to 6.9), whereas those with both LDL cholesterol ?190 mg/dl and an FH mutation demonstrated a 22-fold increased risk (odds ratio: 22.3; 95% confidence interval: 10.7 to 53.2). In an analysis of participants with serial lipid measurements over many years, FH mutation carriers had higher cumulative exposure to LDL cholesterol than noncarriers. CONCLUSIONS:Among participants with LDL cholesterol ?190 mg/dl, gene sequencing identified an FH mutation in <2%. However, for any observed LDL cholesterol, FH mutation carriers had substantially increased risk for CAD.

SUBMITTER: Khera AV

PROVIDER: S-EPMC5405769 | biostudies-literature | 2016 Jun

REPOSITORIES: biostudies-literature

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Diagnostic Yield and Clinical Utility of Sequencing Familial Hypercholesterolemia Genes in Patients With Severe Hypercholesterolemia.

Khera Amit V AV Won Hong-Hee HH Peloso Gina M GM Lawson Kim S KS Bartz Traci M TM Deng Xuan X van Leeuwen Elisabeth M EM Natarajan Pradeep P Emdin Connor A CA Bick Alexander G AG Morrison Alanna C AC Brody Jennifer A JA Gupta Namrata N Nomura Akihiro A Kessler Thorsten T Duga Stefano S Bis Joshua C JC van Duijn Cornelia M CM Cupples L Adrienne LA Psaty Bruce B Rader Daniel J DJ Danesh John J Schunkert Heribert H McPherson Ruth R Farrall Martin M Watkins Hugh H Lander Eric E Wilson James G JG Correa Adolfo A Boerwinkle Eric E Merlini Piera Angelica PA Ardissino Diego D Saleheen Danish D Gabriel Stacey S Kathiresan Sekar S

Journal of the American College of Cardiology 20160403 22

<h4>Background</h4>Approximately 7% of American adults have severe hypercholesterolemia (untreated low-density lipoprotein [LDL] cholesterol ≥190 mg/dl), which may be due to familial hypercholesterolemia (FH). Lifelong LDL cholesterol elevations in FH mutation carriers may confer coronary artery disease (CAD) risk beyond that captured by a single LDL cholesterol measurement.<h4>Objectives</h4>This study assessed the prevalence of an FH mutation among those with severe hypercholesterolemia and de ...[more]

PMID: 27050191

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Project description:Familial hypercholesterolemia (FH) is the most common genetic disorder associated with premature atherosclerotic cardiovascular (CV) disease (ASCVD). However, it still is severely underdiagnosed. Initiating lipid-lowering therapy (LLT) in FH patients early in life can substantially reduce their ASCVD risk. As a result, identifying FH is of the utmost importance. The increasing availability of genetic testing may be useful in this regard. We aimed to evaluate the genetic profiles, clinical characteristics, and gender differences between the first consecutive patients referred for genetic testing with FH clinical suspicion in our institution (a Spanish cohort). Clinical information was reviewed, and all participants were sequenced for the main known genes related to FH: LDLR, APOB, PCSK9 (heterozygous FH), LDLRAP1 (autosomal recessive FH), and two other genes related to hyperlipidaemia (APOE and LIPA). The genetic yield was 32%. Their highest recorded LDLc levels were 294 ± 65 SD mg. However, most patients (79%) were under > 1 LLT medication, and their last mean LDLc levels were 135 ± 51 SD. LDLR c.2389+4A>G was one of the most frequent pathogenic/likely pathogenic variants and its carriers had significantly worse LDLc highest recorded levels (348 ± 61 SD vs. 282 ± 60 SD mg/dL, p = 0.002). Moreover, we identified an homozygous carrier of the pathogenic variant LDLRAP1 c.207delC (autosomal recessive FH). Both clinical and genetic hypercholesterolemia diagnosis was significantly established earlier in men than in women (25 years old ± 15 SD vs. 35 years old ± 19 SD, p = 0.02; and 43 ± 17 SD vs. 54 ± 19 SD, p = 0.02, respectively). Other important CV risk factors were found in 44% of the cohort. The prevalence of family history of premature ASCVD was high, whereas personal history was exceptional. Our finding reaffirms the importance of early detection of FH to initiate primary prevention strategies from a young age. Genetic testing can be very useful. As it enables familial cascade genetic testing, early prevention strategies can be extended to all available relatives at concealed high CV risk.

Project description:Familial hypercholesterolemia (FH) is an autosomal dominant condition with a population prevalence of one in 300-500 (heterozygous) that is characterized by high levels of low-density lipoprotein (LDL) cholesterol, tendon xanthomata, and premature atherosclerosis and coronary heart disease (CHD). FH is caused mainly by mutations in the LDLR gene. However, mutations in other genes including APOB and PCSK9, can give rise to a similar phenotype. Homozygous FH with an estimated prevalence of one in a million is associated with severe hypercholesterolemia with accelerated atherosclerotic CHD in childhood and without treatment, death usually occurs before the age of 30 years. Current approaches for the treatment of homozygous FH include statin-based lipid-lowering therapies and LDL apheresis. Mipomersen is a second-generation antisense oligonucleotide (ASO) targeted to human apolipoprotein B (apoB)-100. This review provides an overview of the pathophysiology and current treatment options for familial hypercholesterolemia and describes novel therapeutic strategies focusing on mipomersen, an antisense apoB synthesis inhibitor. Mipomersen is distributed mainly to the liver where it silences apoB mRNA, thereby reducing hepatic apoB-100 and giving rise to reductions in plasma total cholesterol, LDL-cholesterol, and apoB concentrations in a dose-and time-dependent manner. Mipomersen has been shown to decrease apoB, LDL-cholesterol and lipoprotein(a) in patients with heterozygous and homozygous FH on maximally tolerated lipid-lowering therapy. The short-term efficacy and safety of mipomersen has been established, however, injection site reactions are common and concern exists regarding the long-term potential for hepatic steatosis with this ASO. In summary, mipomersen given alone or in combination with standard lipid-lowering medications shows promise as an adjunct therapy in patients with homozygous or refractory heterozygous FH at high risk of atherosclerotic CHD, who are not at target or are intolerant of statins.

Project description:ImportanceMany pediatric patients with heterozygous familial hypercholesterolemia (HeFH) cannot reach recommended low-density lipoprotein cholesterol (LDL-C) concentrations on statins alone and require adjunct lipid-lowering therapy (LLT); the use of alirocumab in pediatric patients requires evaluation.ObjectiveTo assess the efficacy of alirocumab in pediatric patients with inadequately controlled HeFH.Design, setting, and participantsThis was a phase 3, randomized clinical trial conducted between May 2018 and August 2022 at 43 centers in 24 countries. Pediatric patients aged 8 to 17 years with HeFH, LDL-C 130 mg/dL or greater, and receiving statins or other LLTs were included. Following consecutive enrollment into dosing cohorts, 25 of 99 patients screened for dosing every 2 weeks (Q2W) failed screening; 25 of 104 patients screened for dosing every 4 weeks (Q4W) failed screening. A total of 70 of 74 Q2W patients (95%) and 75 of 79 Q4W patients (95%) completed the double-blind period.InterventionsPatients were randomized 2:1 to subcutaneous alirocumab or placebo and Q2W or Q4W. Dosage was based on weight (40 mg for Q2W or 150 mg for Q4W if <50 kg; 75 mg for Q2W or 300 mg for Q4W if ≥50 kg) and adjusted at week 12 if LDL-C was 110 mg/dL or greater at week 8. After the 24-week double-blind period, patients could receive alirocumab in an 80-week open-label period.Main outcomes and measuresThe primary end point was percent change in LDL-C from baseline to week 24 in each cohort.ResultsAmong 153 patients randomized to receive alirocumab or placebo (mean [range] age, 12.9 [8-17] years; 87 [56.9%] female), alirocumab showed statistically significant reductions in LDL-C vs placebo in both cohorts at week 24. Least squares mean difference in percentage change from baseline was -43.3% (97.5% CI, -56.0 to -30.7; P < .001) Q2W and -33.8% (97.5% CI, -46.4 to -21.2; P < .001) Q4W. Hierarchical analysis of secondary efficacy end points demonstrated significant improvements in other lipid parameters at weeks 12 and 24 with alirocumab. Two patients receiving alirocumab Q4W experienced adverse events leading to discontinuation. No significant difference in adverse event incidence was observed between treatment groups. Open-label period findings were consistent with the double-blind period.Conclusions and relevanceThe findings in this study indicate that alirocumab Q2W or Q4W significantly may be useful for reducing LDL-C and other lipid parameters and be well tolerated in pediatric patients with HeFH inadequately controlled with statins.Trial registrationClinicalTrials.gov Identifier: NCT03510884.

Project description:BackgroundIn a considerable number of patients with a suspected hereditary tumor syndrome (HTS), no underlying germline mutation is detected in the most likely affected genes. The present study aimed to establish and validate a large gene panel for HTS, and determine its diagnostic yield and clinical utility.MethodsThe study cohort comprised 173 patients with suspected, but unexplained, HTS (group U) and 64 HTS patients with a broad spectrum of known germline mutations (group K). All patients in group U presented with early age at onset, multiple tumors, and/or a familial clustering of various tumor types; no germline mutation had been identified during routine diagnostics. Sequencing of leukocyte DNA was performed for the 94 HTS genes of the Illumina TruSight™Cancer Panel and 54 additional HTS genes.ResultsThe sensitivity of the panel to identify known germline variants was 99.6%. In addition to known mutations, a total of 192 rare, potentially pathogenic germline variants in 86 genes were identified. Neither the proportion of rare variants per patient (group K: 0.9 variants; group U: 0.8 variants) nor the proportion of variants in the most frequently mutated, moderately penetrant genes CHEK2 and ATM showed significant inter-group difference. Four of the five patients from group U with a truncating CHEK2 mutation had thyroid cancer, pointing to a broader tumor spectrum in patients with pathogenic CHEK2 variants. In 22% of patients from group K, a further potential causative variant was identified. Here, the most interesting finding was an NF1 nonsense mutation in a child with a known TP53 frameshift mutation. In 17% of patients from group U, potential causative variants were identified. In three of these patients (2%), mutations in PMS2, PTEN, or POLD1 were considered to be causative. In both groups, incidental findings with presumptive predictive value were generated.ConclusionsThe gene panel identified the genetic cause in some prescreened, unexplained HTS patients and generated incidental findings. Some patients harbored predicted pathogenic mutations in more than one established HTS gene, rendering interpretation of the respective alterations challenging. Established moderate risk genes showed an almost equal distribution among patients with known and unexplained disease.

Dataset Information

Diagnostic Yield and Clinical Utility of Sequencing Familial Hypercholesterolemia Genes in Patients With Severe Hypercholesterolemia.

Publications

Diagnostic Yield and Clinical Utility of Sequencing Familial Hypercholesterolemia Genes in Patients With Severe Hypercholesterolemia.

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