Familial hypercholesterolaemia is the most commonly encountered genetic condition that predisposes individuals to premature cardiovascular disease. Nevertheless, most patients are undiagnosed, and treatment is often suboptimal even when the diagnosis seems certain. Advances in molecular technologies are reshaping our understanding of this condition, including revision upwards of the population prevalence. Furthermore, the underlying pathophysiological complexity has been exposed by the range of causative genetic loci, breadth of types and classes of rare disease-causing variants, and polygenic basis of the phenotype in many patients. Genetic testing is not always helpful or definitive. Familial hypercholesterolaemia can be envisioned as a group of related disorders, of which the classic 'textbook' phenotype is a subset. Features such as clinical stigmata, family history of dyslipidaemia or cardiovascular disease, and presence of a rare pathogenic variant all increase diagnostic certainty. However, even in the absence of these elements, the essential feature remains an elevated level of plasma LDL cholesterol, which alone should prompt a dialogue between the care provider and the patient on lifestyle modification and lipid-lowering therapy as the foundation of a long-term strategy to prevent or delay the onset of cardiovascular disease.

Background Homozygous familial hypercholesterolaemia is a rare life-threatening disease characterized by markedly elevated low-density lipoprotein cholesterol (LDL-C) concentrations and accelerated atherosclerosis. The presence of double gene defects in the LDL-Receptor, either the same defect (homozygous) or two different LDL-raising mutations (compound heterozygotes) or other variants, identify the homozygous phenotype (HopFH). Apheresis is a procedure in which plasma is separated from red blood cells before the physical removal of LDL-C or the LDL-C is directly removed from whole blood. It is currently the treatment of choice for patients with HopFH whose LDL-C levels are not able to be reduced to target levels with conventional lipid-lowering drug therapy. Design The aim of this study is to report a cohort of six paediatric patients and to evaluate the long term efficacy of combined medical therapy and LDL-apheresis on LDL-C reduction. Methods We collected data from six children with confirmed diagnosis of HopFH (two females and four males; age range at diagnosis 3-8 years, mean 6 ± 1 years) from a single clinical hospital in Italy from 2007 to 2017. Results Clinical manifestations and outcomes may greatly vary in children with HopFH. Medical therapy and LDL-apheresis for the severe form should be started promptly in order to prevent cardiovascular disease. Conclusions Lipoprotein apheresis is a very important tool in managing patients with HopFH at high risk of cardiovascular disease. Based on our experience and the literature data, the method is feasible in very young children, efficient regarding biological results and cardiac events, and safe with minor side-effects and technical problems. We advise treating homozygous and compound heterozygous children as soon as possible.

Familial hypercholesterolaemia (FH) is a devastating genetic disease that leads to extremely high cholesterol levels and severe cardiovascular disease, mainly caused by mutations in any of the main genes involved in low-density lipoprotein cholesterol (LDL-C) uptake. Among these genes, mutations in the LDL receptor () are responsible for 80%-90% of the FH cases. The severe homozygous variety (HoFH) is not successfully treated with standard cholesterol-lowering therapies, and more aggressive strategies must be considered to mitigate the effects of this disease, such as weekly/biweekly LDL apheresis. However, development of new therapeutic approaches is needed to cure HoFH. Because HoFH is mainly due to mutations in the , this disease has been proposed as an ideal candidate for gene therapy. Several preclinical studies have proposed that the transference of functional copies of the gene reduces circulating LDL-C levels in several models of HoFH, which has led to the first clinical trials in humans. Additionally, the recent development of clustered regularly interspaced short palindromic repeat/CRISPR-associated 9 technology for genome editing has opened the door to therapies aimed at directly correcting the specific mutation in the endogenous gene. In this article, we review the genetic basis of the FH disease, paying special attention to the severe HoFH as well as the challenges in its diagnosis and clinical management. Additionally, we discuss the current therapies for this disease and the new emerging advances in gene therapy to target a definitive cure for this disease.

AIMS:Familial hypercholesterolemia (FH) is the most common genetic disorder in medicine, with a prevalence of 1/250. Affected individuals have elevated low-density lipoprotein cholesterol (LDL-C) and an increased lifetime risk of atherosclerotic cardiovascular disease (ASCVD). The diagnosis of FH is based on algorithms that include LDL-C levels, physical manifestations, family history of high LDL-C and premature ASCVD, and, more recently, genetic testing. We sought to determine the impact of genetic testing on the: 1) diagnosis of 'definite familial hypercholesterolemia', 2) initiation and adherence of lipid-lowering therapy and 3) risk of ASCVD. METHODS:We performed a systematic review and meta-analysis, pooling odds ratios and 95% confidence intervals for ASCVD from studies comparing risk estimates in individuals harboring FH-causing variants and unaffected individuals. RESULTS:After screening 3304 unique publications, 56 studies were included in the analysis. 1) Genetic testing provided confirmation of FH in 28-80%, over clinical criteria alone, depending on the diagnostic algorithm and the method of analysis. In two large population-based studies comprising 76,751 individuals, an FH-causing variant was identified in only 1.7-2.5% of subjects with an LDL-C > 4.9 mmol/L (190 mg/dL). 2) A confirmed molecular diagnosis increased lipid-lowering therapy adherence (five studies,  = 4181 definite FH). 3) Loss-of-function variant of the were at a markedly increased risk of myocardial infarction (odds ratio 6.77, 95% confidence interval 4.75-9.66), and patients with a milder (hypomorphic) pathogenic change had a 4.4-fold increase in risk (odds ratio 4.4, 95% confidence interval 2.34-8.26), compared with controls. CONCLUSION:DNA sequencing confirms the diagnosis of FH but has a poor yield in unselected patients whose sole criterion is an elevated LDL-C. Initiation and adherence to treatment is improved. The risk of ASCVD is 4.4- to 6.8-fold increased in patients with an FH-causing variant compared with controls, depending on the severity of the DNA change.

Background Familial hypercholesterolemia is the elective clinical condition that deserves the maximal personalisation in lipid-lowering therapy, especially in the presence of statin intolerance. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors represent a promising approach to lower low-density lipoprotein (LDL) cholesterol. Methods We enrolled 18 patients (mean age 62 ± 8 years, 72% men) affected by heterozygous familial hypercholesterolemia and cardiovascular disease, with a history of statin intolerance assigned to PCSK9 inhibitors. Six patients were also on LDL apheresis. Associated Lp(a)-hyperlipoproteinemia (defined as >60 mg/dl) was observed in two out of 18 subjects. PCSK9 inhibitor injectable monoclonal antibodies were administered, every 2 weeks, on top of patient therapy for 12 ± 4 weeks (evolocumab in 15 subjects, alirocumab in three subjects). Results After 3 months (12 ± 4 weeks) of therapy, a decrease in total cholesterol (-35%), LDL cholesterol (-51%) and Lp(a) levels (-20%) was observed. Five out of 18 patients reached LDL cholesterol levels of <70 mg/dl, seven showed LDL cholesterol values between 71 and 100 mg/dl, and six out of 18 still had LDL cholesterol levels above 100 mg/dl. Among the six patients with LDL cholesterol levels >100 mg/dl, three were already on LDL apheresis before the PCSK9 inhibitor treatment, while three were referred to LDL apheresis treatment. Adverse events were reported in two out of 18 patients on evolocumab: one presented with flu-like syndrome and the other reported episodes of mild difficulty in maintaining concentration. Conclusions PCSK9 inhibitors represent a novel therapeutic tool for patients with familial hypercholesterolemia who are intolerant to statins. However, more data are needed before cleaning up the old therapeutic armamentarium, such as LDL apheresis, which is likely to preserve its valuable role also in the new lipid-lowering era.

OBJECTIVE:Patients with familial hypercholesterolemia (FH) are at high risk for premature atherosclerotic cardiovascular disease (ASCVD), especially because of long-term exposure to high low-density lipoprotein cholesterol levels. It has been reported that low-density lipoprotein-lowering therapy delays the onset of ASCVD. However, it still remains difficult to prevent it. Therefore, novel biomarkers and therapeutic targets are necessary to evaluate and prevent atherosclerosis in FH. The aim of this study was to investigate associations of cholesterol efflux capacity with the presence of ASCVD and clinical features in patients with heterozygous FH. APPROACH AND RESULTS:We measured cholesterol efflux capacity in 227 patients with heterozygous FH under pharmaceutical treatment. Seventy-six (33.5%) of them were known to have ASCVD. In a logistic-regression analysis adjusted for risk factors, increased efflux capacity was associated with decreased risk of ASCVD even after the addition of high-density lipoprotein cholesterol level as a covariate (odds ratio per 1-SD increase, 0.95; 95% confidence interval, 0.90-0.99; P<0.05). Decreased cholesterol efflux capacity was associated with the presence of corneal arcus after adjusting for age and sex. In addition, inverse relationships between cholesterol efflux capacity and Achilles tendon thickness, as well as carotid intima-media thickness, were observed after adjustment for age, sex, and traditional cardiovascular risk factors. CONCLUSIONS:Cholesterol efflux capacity was independently and inversely associated with the presence of ASCVD in heterozygous FH. In view of residual risks after treatment with statins, cholesterol efflux capacity might be a novel biomarker and a therapeutic target for preventing atherosclerosis in patients with FH.

Familial hypercholesterolemia (FH) is the most common inherited form of dyslipidemia and a major cause of premature cardiovascular disease. Management of FH mainly relies on the efficiency of treatments that reduce plasma low-density lipoprotein (LDL) cholesterol (LDL-C) concentrations. MicroRNAs (miRs) have been suggested as emerging regulators of plasma LDL-C concentrations. Notably, there is evidence showing that miRs can regulate the post-transcriptional expression of genes involved in the pathogenesis of FH, including LDLR, APOB, PCSK9, and LDLRAP1. In addition, many miRs are located in genomic loci associated with abnormal levels of circulating lipids and lipoproteins in human plasma. The strong regulatory effects of miRs on the expression of FH-associated genes support of the notion that manipulation of miRs might serve as a potential novel therapeutic approach. The present review describes miRs-targeting FH-associated genes that could be used as potential therapeutic targets in patients with FH or other severe dyslipidemias.

BACKGROUND:Heterozygous familial hypercholesterolemia (HeFH) is one of the most common genetic diseases in the world and an important cause of premature cardiovascular (CV) disease. The purpose of this study was to characterize the clinical features, current treatment patterns, and CV outcomes of patients with HeFH in British Columbia, Canada. METHODS:We conducted a longitudinal observational study of patients with HeFH attending a specialized lipid clinic. We collected data on lipid levels, medication use, and CV events at baseline and last follow-up. RESULTS:We recruited 339 patients with clinically diagnosed HeFH, with a total of 3700 person-years of follow-up. The mean low-density lipoprotein cholesterol (LDL-C) level was 5.9 mmol/L at baseline and 3.7 mmol/L at last follow-up. Use of lipid-lowering therapy (LLT) increased from 35.7% at baseline to 84.7% at last follow-up. A ≥ 50% reduction in LDL-C level was achieved in 34.5% of patients, and an LDL-C level ≤ 2 mmol/L was seen in 8.3%. The overall CV event rate in this cohort was 33.5/1000 person-years. Among patients who had a CV event during follow-up, 59% experienced a recurrent event within 5 years. CONCLUSIONS:These data contribute to our understanding of contemporary trends in the management of patients with HeFH in Canada. Despite a majority of patients receiving LLT, few patients reached high-risk lipid targets. These data highlight important opportunities to improve the care of patients with HeFH.

Homozygous familial hypercholesterolemia (HoFH), the severest form of familial hypercholesterolemia (FH), is characterized by very high LDL-cholesterol levels and a high frequency of coronary heart disease. The disease is caused by the presence of either a pathogenic variant at homozygous status or of two pathogenic variants at compound heterozygous status in the , , genes. We retrospectively analyzed data of 23 HoFH patients (four children and 19 adults) identified during the genetic screening of 724 FH patients. Genetic screening was performed by sequencing FH causative genes and identifying large rearrangements of . Among the HoFH patients, four out of 23 (17.4%) were true homozygotes, whereas 19 out of 23 (82.6%) were compound heterozygotes for variants in the gene. Basal LDL-cholesterol was 12.9 ± 2.9 mmol/L. LDL-cholesterol levels decreased to 7.2 ± 1.8 mmol/L when treated with statin/ezetimibe and to 5.1 ± 3.1 mmol/L with anti- antibodies. Homozygous patients showed higher basal LDL-cholesterol and a poorer response to therapy compared with compound heterozygotes. Since 19 unrelated patients were identified in the Campania region (6,000,000 inhabitants) in southern Italy, the regional prevalence of HoFH was estimated to be at least 1:320,000. In conclusion, our results revealed a worse phenotype for homozygotes compared with compound heterozygotes, thereby highlighting the role of genetic screening in differentiating one genetic status from the other.

Familial hypercholesterolaemia (FH) is a dominantly inherited disorder present from birth that markedly elevates plasma low-density lipoprotein (LDL) cholesterol and causes premature coronary heart disease. There are at least 20 million people with FH worldwide, but the majority remains undetected and current treatment is often suboptimal.To address this major gap in coronary prevention we present, from an international perspective, consensus-based guidance on the care of FH. The guidance was generated from seminars and workshops held at an international symposium. The recommendations focus on the detection, diagnosis, assessment and management of FH in adults and children, and set guidelines for clinical purposes. They also refer to best practice for cascade screening and risk notifying and testing families for FH, including use of genetic testing. Guidance on treatment is based on risk stratification, management of non-cholesterol risk factors and safe and effective use of LDL lowering therapies. Recommendations are given on lipoprotein apheresis. The use of emerging therapies for FH is also foreshadowed.This international guidance acknowledges evidence gaps, but aims to make the best use of contemporary practice and technology to achieve the best outcomes for the care of FH. It should accordingly be employed to inform clinical judgment and be adjusted for country-specific and local healthcare needs and resources.

BACKGROUND:Familial hypercholesterolemia (FH) is the most common genetic disorder associated with premature atherosclerotic cardiovascular disease (ASCVD). There are sparse data on attainment of treatment targets; large registries that reflect real-life clinical practice can uniquely provide this information. OBJECTIVES:We sought to evaluate the achievement of low-density lipoprotein cholesterol (LDL-C) treatment goals in FH patients enrolled in a large national registry. METHODS:The SAFEHEART study (Spanish Familial Hypercholesterolemia Cohort Study) is a large, ongoing registry of molecularly defined patients with heterozygous FH treated in Spain. The attainment of guideline-recommended plasma LDL-C goals at entry and follow-up was investigated in relation to use of lipid-lowering therapy (LLT). RESULTS:The study recruited 4,132 individuals (3,745 of whom were ≥18 years of age); 2,752 of those enrolled were molecularly diagnosed FH cases. Mean follow-up was 5.1 ± 3.1 years; 71.8% of FH cases were on maximal LLT, and an LDL-C treatment target <100 mg/dl was reached by only 11.2% of patients. At follow-up, there was a significant increase in the use of ezetimibe, drug combinations with statins, and maximal LLT. The presence of type 2 diabetes mellitus, a defective allele mutation, ezetimibe use, and the absence of previous ASCVD were predictors of the attainment of LDL-C goals. CONCLUSIONS:Despite the use of intensified LLT, many FH patients continue to experience high plasma LDL-C levels and, consequently, do not achieve recommended treatment targets. Type of LDL-receptor mutation, use of ezetimibe, coexistent diabetes, and ASCVD status can bear significantly on the likelihood of attaining LDL-C treatment goals.

BACKGROUND:Familial hypercholesterolemia (FH) is the most frequent genetic disorder seen clinically and is characterized by increased LDL cholesterol (LDL-C) (>95th percentile), family history of increased LDL-C, premature atherosclerotic cardiovascular disease (ASCVD) in the patient or in first-degree relatives, presence of tendinous xanthomas or premature corneal arcus, or presence of a pathogenic mutation in the , , or genes. A diagnosis of FH has important clinical implications with respect to lifelong risk of ASCVD and requirement for intensive pharmacological therapy. The concentration of baseline LDL-C (untreated) is essential for the diagnosis of FH but is often not available because the individual is already on statin therapy. METHODS:To validate a new algorithm to impute baseline LDL-C, we examined 1297 patients. The baseline LDL-C was compared with the imputed baseline obtained within 18 months of the initiation of therapy. We compared the percent reduction in LDL-C on treatment from baseline with the published percent reductions. RESULTS:After eliminating individuals with missing data, nonstandard doses of statins, or medications other than statins or ezetimibe, we provide data on 951 patients. The mean ± SE baseline LDL-C was 243.0 (2.2) mg/dL [6.28 (0.06) mmol/L], and the mean ± SE imputed baseline LDL-C was 244.2 (2.6) mg/dL [6.31 (0.07) mmol/L] ( = 0.48). There was no difference in response according to the patient's sex or in percent reduction between observed and expected for individual doses or types of statin or ezetimibe. CONCLUSIONS:We provide a validated estimation of baseline LDL-C for patients with FH that may help clinicians in making a diagnosis.

Familial hypercholesterolaemia is a common inherited disorder characterized by abnormally elevated serum levels of low-density lipoprotein (LDL) cholesterol from birth, which in time can lead to cardiovascular disease (CVD). Most cases are caused by autosomal dominant mutations in LDLR, which encodes the LDL receptor, although mutations in other genes coding for proteins involved in cholesterol metabolism or LDLR function and processing, such as APOB and PCSK9, can also be causative, although less frequently. Several sets of diagnostic criteria for familial hypercholesterolaemia are available; common diagnostic features are an elevated LDL cholesterol level and a family history of hypercholesterolaemia or (premature) CVD. DNA-based methods to identify the underlying genetic defect are desirable but not essential for diagnosis. Cascade screening can contribute to early diagnosis of the disease in family members of an affected individual, which is crucial because familial hypercholesterolaemia can be asymptomatic for decades. Clinical severity depends on the nature of the gene that harbours the causative mutation, among other factors, and is further modulated by the type of mutation. Lifelong LDL cholesterol-lowering treatment substantially improves CVD-free survival and longevity. Statins are the first-line therapy, but additional drugs, such as ezetimibe, bile acid sequestrants, PCSK9 inhibitors and other emerging therapies, are often required.

Familial hypercholesterolemia (FH) is a common genetic condition characterized by elevated plasma levels of low-density lipoprotein cholesterol (LDL-C), premature atherosclerotic cardiovascular disease, and considerable unmet medical need with conventional LDL-C-lowering therapies. Between 2012 and 2015, the US Food and Drug Administration approved four novel LDL-C-lowering agents for use in patients with FH based on the pronounced LDL-C-lowering efficacy of these medicines. We review the four novel approved agents, as well as promising LDL-C-lowering agents in clinical development, with a focus on their mechanism of action, efficacy in FH cohorts, and safety.

OBJECTIVE:Evolocumab, a PCSK9 (proprotein convertase subtilisin kexin type 9)-neutralizing antibody, lowers low-density lipoprotein cholesterol (LDL-C) in homozygous familial hypercholesterolemic (HoFH) patients with reduced LDLR (low-density lipoprotein receptor) function. However, their individual responses are highly variable, even among carriers of identical LDLR genetic defects. We aimed to elucidate why HoFH patients variably respond to PCSK9 inhibition. APPROACH AND RESULTS:Lymphocytes were isolated from 22 HoFH patients enrolled in the TAUSSIG trial (Trial Assessing Long Term Use of PCSK9 Inhibition in Subjects With Genetic LDL Disorders). Ten patients were true homozygotes (FH1/FH1) and 5 identical compound heterozygotes (FH1/FH2). Lymphocytes were plated with or without mevastatin, recombinant PCSK9 (rPCSK9), or a PCSK9-neutralizing antibody. Cell surface LDLR expression was analyzed by flow cytometry. All HoFH lymphocytes had reduced cell surface LDLR expression compared with non-FH lymphocytes, for each treatment modality. Lymphocytes from FH1/FH2 patients (LDLR defective/negative) displayed the lowest LDLR expression levels followed by lymphocytes from FH1/FH1 patients (defective/defective). Mevastatin increased, whereas rPCSK9 reduced LDLR expression. The PCSK9-neutralizing antibody restored LDLR expression. Lymphocytes displaying higher LDLR expression levels were those isolated from patients presenting with lowest levels of LDL-C and apolipoprotein B, before and after 24 weeks of evolocumab treatment. These negative correlations remained significant in FH1/FH1 patients and appeared more pronounced when patients with apolipoprotein E3/E3 genotypes were analyzed separately. Significant positive correlations were found between the levels of LDLR expression and the percentage reduction in LDL-C on evolocumab treatment. CONCLUSIONS:Residual LDLR expression in HoFH is a major determinant of LDL-C levels and seems to drive their individual response to evolocumab.

Familial hypercholesterolemia (FH) causes elevation of low-density lipoprotein cholesterol (LDL-C) in blood and carries an increased risk of early-onset cardiovascular disease. A caveat for exploration of new therapies for FH is the lack of adequate experimental models. We have created a comprehensive FH stem cell model with differentiated hepatocytes (iHeps) from human induced pluripotent stem cells (iPSCs), including genetically engineered iPSCs, for testing therapies for FH. We used FH iHeps to assess the effect of simvastatin and proprotein convertase subtilisin/kexin type 9 (PCSK9) antibodies on LDL-C uptake and cholesterol lowering in vitro. In addition, we engrafted FH iHeps into the liver of Ldlr/Rag2/Il2rg mice, and assessed the effect of these same medications on LDL-C clearance and endothelium-dependent vasodilation in vivo. Our iHep models recapitulate clinical observations of higher potency of PCSK9 antibodies compared with statins for reversing the consequences of FH, demonstrating the utility for preclinical testing of new therapies for FH patients.

BACKGROUND:Familial hypercholesterolemia (FH) is known to be underdiagnosed and undertreated. The prevalence of heterozygous FH is estimated to be 1 in 500. Nevertheless, a recent meta-analysis of screening in the general population seems to show that the prevalence of FH is more likely to be 1 in 250. METHODS:Analysis was based on the third French MONICA and MONALISA population surveys. Participants were randomly recruited in 1995 and 2005 from the general population of 3 regions of France. FH was diagnosed using a modified version of the Dutch Lipid Clinic Network (DLCN) without genetic testing. RESULTS:The DLCN score was assessed in 7928 participants aged 35 to 74 years; 50% were men. The prevalence of definite or probable FH was 0.85% (95% CI, 0.63-1.06). Among patients with definite or probable FH, 12% had histories of premature cardiovascular disease (vs less than 1% among subjects without FH; P < 0.0001), 70% were treated (13% with high-intensity, 83% with moderate-intensity, and 4% with low-intensity statin therapy), 90% had cholesterol screening within the past 12 months, and 97% were aware of their hypercholesterolemia. None reached the recommended low-density lipoprotein cholesterol (LDL-C) target (< 2.5 or < 1.8 mmol/L for subjects in primary prevention vs in secondary prevention or with diabetes, respectively), with a mean distance to target of 3.0 mmol/L. CONCLUSIONS:In a sample from the French general population aged 35 to 74 years, the prevalence of FH was close to 1 in 120, and the patients with FH were undertreated.

BACKGROUND:Genetic screening programs in unselected individuals with increased levels of low-density lipoprotein cholesterol (LDL-C) have shown modest results in identifying individuals with familial hypercholesterolemia (FH). OBJECTIVES:This study assessed the prevalence of genetically confirmed FH in patients with acute coronary syndrome (ACS) and compared the diagnostic performance of FH clinical criteria versus FH genetic testing. METHODS:Genetic study of 7 genes (LDLR, APOB, PCSK9, APOE, STAP1, LDLRAP1, and LIPA) associated with FH and 12 common alleles associated with polygenic hypercholesterolemia was performed in 103 patients with ACS, age ≤65 years, and LDL-C levels ≥160 mg/dl. Dutch Lipid Clinic (DLC) and Simon Broome (SB) FH clinical criteria were also applied. RESULTS:The prevalence of genetically confirmed FH was 8.7% (95% confidence interval [CI]: 4.3% to 16.4%; n = 9); 29% (95% CI: 18.5% to 42.1%; n = 18) of patients without FH variants had a score highly suggestive of polygenic hypercholesterolemia. The prevalence of probable to definite FH according to DLC criteria was 27.2% (95% CI: 19.1% to 37.0%; n = 28), whereas SB criteria identified 27.2% of patients (95% CI: 19.1% to 37.0%; n = 28) with possible to definite FH. DLC and SB algorithms failed to diagnose 4 (44%) and 3 (33%) patients with genetically confirmed FH, respectively. Cascade genetic testing in first-degree relatives identified 6 additional individuals with FH. CONCLUSIONS:The prevalence of genetically confirmed FH in patients with ACS age ≤65 years and with LDL-C levels ≥160 mg/dl is high (approximately 9%). FH clinical algorithms do not accurately classify patients with FH. Genetic testing should be advocated in young patients with ACS and high LDL-C levels to allow prompt identification of patients with FH and relatives at risk.

BACKGROUND:Homozygous familial hypercholesterolemia (HoFH), a rare genetic disorder, is characterized by extremely elevated levels of low-density lipoprotein cholesterol (LDL-C) and accelerated atherosclerotic cardiovascular disease. Statin treatment starts at diagnosis, but no statin has been formally evaluated in, or approved for, HoFH children. OBJECTIVES:The authors sought to assess the LDL-C efficacy of rosuvastatin versus placebo in HoFH children, and the relationship with underlying genetic mutations. METHODS:This was a randomized, double-blind, 12-week, crossover study of rosuvastatin 20 mg versus placebo, followed by 12 weeks of open-label rosuvastatin. Patients discontinued all lipid-lowering treatment except ezetimibe and/or apheresis. Clinical and laboratory assessments were performed every 6 weeks. The relationship between LDL-C response and genetic mutations was assessed by adding children and adults from a prior HoFH rosuvastatin trial. RESULTS:Twenty patients were screened, 14 randomized, and 13 completed the study. The mean age was 10.9 years; 8 patients were on ezetimibe and 7 on apheresis. Mean LDL-C was 481 mg/dl (range: 229 to 742 mg/dl) on placebo and 396 mg/dl (range: 130 to 700 mg/dl) on rosuvastatin, producing a mean 85.4 mg/dl (22.3%) difference (p = 0.005). Efficacy was similar regardless of age or use of ezetimibe or apheresis, and was maintained for 12 weeks. Adverse events were few and not serious. Patients with 2 defective versus 2 negative LDL receptor mutations had mean LDL-C reductions of 23.5% (p = 0.0044) and 14% (p = 0.038), respectively. CONCLUSIONS:This first-ever pediatric HoFH statin trial demonstrated safe and effective LDL-C reduction with rosuvastatin 20 mg alone or added to ezetimibe and/or apheresis. The LDL-C response in children and adults was related to underlying genetic mutations. (A Study to Evaluate the Efficacy and Safety of Rosuvastatin in Children and Adolescents With Homozygous Familial Hypercholesterolemia [HYDRA]; NCT02226198).

Familial hypercholesterolemia (FH) is a frequent genetic disorder characterized by elevated low-density lipoprotein (LDL)-cholesterol (LDL-C) levels and early onset of atherosclerotic cardiovascular disease. FH is caused by mutations in genes that regulate LDL catabolism, mainly the LDL receptor (LDLR), apolipoprotein B (APOB) and gain of function of proprotein convertase subtilisin kexin type 9 (PCSK9). However, the phenotype may be encountered in individuals not carrying the latter monogenic defects, in approximately 20% of these effects of polygenes predominate, and in many individuals no molecular defects are encountered at all. These so-called FH phenocopy individuals have an elevated atherosclerotic cardiovascular disease risk in comparison with normolipidemic individuals but this risk is lower than in those with monogenic disease. Individuals with FH are exposed to elevated LDL-C levels since birth and this explains the high cardiovascular, mainly coronary heart disease, burden of these subjects. However, recent studies show that this risk is heterogenous and depends not only on high LDL-C levels but also on presence of previous cardiovascular disease, a monogenic cause, male sex, smoking, hypertension, diabetes, low HDL-cholesterol, obesity and elevated lipoprotein(a). This heterogeneity in risk can be captured by risk equations like one from the SAFEHEART cohort and by detection of subclinical coronary atherosclerosis. High dose high potency statins are the main stain for LDL-C lowering in FH, however, in most situations these medications are not powered enough to reduce cholesterol to adequate levels. Ezetimibe and PCSK9 inhibitors should also be used in order to better treat LDL-C in FH patients.

BACKGROUND:Familial hypercholesterolemia (FH) is a common genetic disorder of severely elevated low-density lipoprotein (LDL) cholesterol, characterized by premature atherosclerotic cardiovascular disease. Although copy number variations (CNVs) are a large-scale mutation-type capable of explaining FH cases, they have been, to date, assessed only in the LDLR gene. Here, we performed novel CNV screening in additional FH-associated genes using a next-generation sequencing-based approach. METHODS:In 704 patients with FH, we sequenced FH-associated genes APOB, PCSK9, LDLRAP1, APOE, STAP1, LIPA, and ABCG5/8 using our LipidSeq targeted next-generation sequencing panel. Bioinformatic tools were applied to LipidSeq data for CNV screening, and identified CNVs were validated using whole-exome sequencing and microarray-based copy number analyses. RESULTS:We identified a whole-gene duplication of PCSK9 in 2 unrelated Canadian FH index cases; this PCSK9 CNV was also found to cosegregate with affected status in family members. Features in affected individuals included severely elevated LDL cholesterol levels that were refractory to intensive statin therapy, pronounced clinical stigmata, premature cardiovascular events, and a plasma PCSK9 of approximately 5000 ng/mL in 1 index case. We found no CNVs in APOB, LDLRAP1, APOE, STAP1, LIPA, and ABCG5/8 in our cohort of 704 FH individuals. CONCLUSIONS:Here, we report the first description of a CNV affecting the PCSK9 gene in FH. This finding is associated with a profound FH phenotype and the highest known plasma PCSK9 level reported in a human. This finding also has therapeutic relevance, as elevated PCSK9 levels may limit the efficacy of high-dose statin therapy and also PCSK9 inhibition.

Background Patients with homozygous familial hypercholesterolemia are at high risk of cardiovascular disease due to high low-density lipoprotein (LDL)-cholesterol levels. Cardiovascular disease outcome studies are impossible to conduct, due to the rarity of homozygous familial hypercholesterolemia. We modelled the potential efficacy of lomitapide, a microsomal transfer protein inhibitor, on major adverse cardiovascular events (MACEs) and survival. Design We calculated the effect on cardiovascular outcomes of a 38% plasma LDL-cholesterol reduction induced by lomitapide. Methods Age-dependent hazards and treatment-dependent hazard ratios for mortality and time to first MACE were calculated from an observational study of 149 South African homozygous familial hypercholesterolemia patients. Cardiovascular-related mortality hazards were derived by adjusting for general population non-cardiovascular-related mortality. For every mmol/L LDL-cholesterol reduction, a relative risk reductions of 23% (mortality) and 15% (major adverse cardiovascular events) were observed. Results For the most robust model, baseline median survival with current treatments (LDL-cholesterol 8.7 mmol/L) was 48 years. In the survival benefit analysis, starting lomitapide at age 18 years and reducing LDL-cholesterol by 3.3 mmol/L from baseline would increase life expectancy by 11.2 years and delay the time to first MACE by 5.7 years. Analysis suggested lifetime lomitapide treatment could increase median life expectancy by 11.7 years and time to first MACE by 6.7 years. Conclusion Our modelling analyses show that additional LDL-cholesterol lowering by lomitapide may increase life expectancy in patients with homozygous familial hypercholesterolemia. Further clinical studies are warranted to determine the cardiovascular morbidity and mortality benefits of lomitapide.

BACKGROUND AND AIMS:Familial hypercholesterolemia (FH) is amongst the most common genetic disorders encountered in primary care. Yet, only a minority of affected patients is diagnosed and treated. This interim analysis of the CaRe High Registry aims at examining the state of treatment and attainment of lipid goals in German FH patients. METHODS:The CaRe High registry includes FH patients from lipid clinics and private practices. Data have been collected using questionnaires filled in by the recruiting physicians and by interviewing the participating patients. RESULTS:We examined 512 F H patients diagnosed according to clinical criteria. Median age at the time of the first FH diagnosis was 39 (25th and 75th percentile: 27-50) years, median treatment naïve LDL cholesterol (LDL-C) was 239.4 mg/dl (6.19 mmol/l), 25th to 75th percentile 191.8-342.5 mg/dl (4.96-8.86 mmol/l). 27% of the participants did not receive lipid-lowering drugs. Among the patients treated with lipid-lowering drugs, 19% received a PCSK9 inhibitor (PCSK9i) in combination with a statin, 9% were treated with a PCSK9i alone and 3% were treated with a combination of PCSK9i and a non-statin drug. Patients with pre-existing CVD were more likely to be treated with lipid-lowering drugs and more likely to receive a PCSK9i, but LDL-C targets were only achieved by a minority of patients (<20%). Gap to target LDL-C was lowest and the median achieved LDL-C reduction was 1.4 times higher with PCSK9i treatment than with (oral) lipid-lowering therapy without PCSK9i. CONCLUSIONS:The Care High registry has included patients with the typical clinical features of familial hypercholesterolemia. PCSK9i treatment in addition to standard therapy allows attainment of target values in many patients with initially very high LDL-C.

Familial hypercholesterolemia (FH) is an autosomal co-dominant genetic disorder characterized by elevated low-density lipoprotein cholesterol levels and increased risk for premature cardiovascular disease. It is under-diagnosed, yet early detection and treatment are critical to limit premature atherosclerotic disease. High-intensity statins are the mainstay of treatment, which should be started as early as possible in homozygous FH and as soon as the diagnosis of heterozygous FH is made in adults. Combination therapy is often necessary in FH patients and can include the addition of ezetimibe and bile acid sequestrants. Lipoprotein apheresis is used when pharmacotherapy is inadequate, especially for those with homozygous FH and some patients with severe heterozygous FH. Mipomersen and lomitapide are also indicated for patients with homozygous FH. The recently approved PCSK9 inhibitors, alirocumab and evolocumab, are a promising treatment and outcome studies are ongoing. This article reviews the pathophysiology, diagnosis, and management of FH.

BACKGROUND AND AIMS:Although familial hypercholesterolemia (FH) is one of the most common genetic disorders, it remains largely underdiagnosed and undertreated. The Hellenic Atherosclerosis Society has established the Hellenic Familial Hypercholesterolemia (HELLAS-FH) Registry, part of the Familial Hypercholesterolemia Studies Collaboration (FHSC), to evaluate the characteristics and management of patients with FH in Greece. METHODS:Patients with diagnosed FH were recruited by a network of sites throughout Greece. The prevalence of cardiovascular disease (CVD) risk factors, as well as management of FH, was recorded. RESULTS:This interim analysis included 1093 patients (556 male; 950 adults). The median age of FH diagnosis was 42.2 years (interquartile range 27.2-53.0). A family history of CVD was present in 47.8%, while 21.1% of patients had a personal history of CVD. At diagnosis, low-density lipoprotein cholesterol (LDL-C) was 241 ± 76 mg/dL in adults and 229 ± 57 mg/dL in children. Overall, 63.1% of the patients were receiving hypolipidemic drug treatment, mainly statins, at inclusion in the registry. Mean LDL-C of patients receiving drug treatment was 154 ± 76 mg/dL in adults and 136 ± 47 mg/dL in children. The majority of treated patients (87.9%) did not achieve LDL-C targets. CONCLUSIONS:FH in Greece is characterized by a significant delay in diagnosis and a high prevalence of both family and personal history of established CVD. The vast majority of FH patients do not achieve LDL-C targets. Improved awareness and management of FH are definitely needed.

Although awareness of familial hypercholesterolemia (FH) is increasing, this common, potentially fatal, treatable condition remains underdiagnosed. Despite FH being a genetic disorder, genetic testing is rarely used. The Familial Hypercholesterolemia Foundation convened an international expert panel to assess the utility of FH genetic testing. The rationale includes the following: 1) facilitation of definitive diagnosis; 2) pathogenic variants indicate higher cardiovascular risk, which indicates the potential need for more aggressive lipid lowering; 3) increase in initiation of and adherence to therapy; and 4) cascade testing of at-risk relatives. The Expert Consensus Panel recommends that FH genetic testing become the standard of care for patients with definite or probable FH, as well as for their at-risk relatives. Testing should include the genes encoding the low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), and proprotein convertase subtilisin/kexin 9 (PCSK9); other genes may also need to be considered for analysis based on patient phenotype. Expected outcomes include greater diagnoses, more effective cascade testing, initiation of therapies at earlier ages, and more accurate risk stratification.

RATIONALE:Familial hypercholesterolemia is a genetic disorder that arises because of loss-of-function mutations in the low-density lipoprotein receptor (LDLR) and homozygous familial hypercholesterolemia is a candidate for gene therapy using adeno-associated viral vectors. Proprotein convertase subtilisin/kexin type 9 (PCSK9) and inducible degrader of LDLR (IDOL) negatively regulate LDLR protein and could dampen adeno-associated viral vector encoded LDLR expression. OBJECTIVE:We sought to create vectors expressing gain-of-function human LDLR variants that are resistant to degradation by human PCSK9 (hPCSK9) and IDOL and thereby enhance hepatic LDLR protein abundance and plasma LDL cholesterol reduction. METHODS AND RESULTS:Amino acid substitutions were introduced into the coding sequence of human LDLR cDNA to reduce interaction with hPCSK9 and human IDOL. A panel of mutant human LDLRs was initially screened in vitro for escape from PCSK9. The variant human LDLR-L318D was further evaluated using a mouse model of homozygous familial hypercholesterolemia lacking endogenous LDLR and apolipoprotein B mRNA editing enzyme catalytic, APOBEC-1 (double knockout). Administration of wild-type human LDLR to double knockout mice, expressing hPCSK9, led to diminished LDLR activity. However, LDLR-L318D was resistant to hPCSK9-mediated degradation and effectively reduced cholesterol levels. Similarly, the LDLR-K809R\C818A construct avoided human IDOL regulation and achieved stable reductions in serum cholesterol. An adeno-associated viral vector serotype 8.LDLR-L318D\K809R\C818A vector that carried all 3 amino acid substitutions conferred partial resistance to both hPCSK9- and human IDOL-mediated degradation. CONCLUSIONS:Amino acid substitutions in the human LDLR confer partial resistance to PCSK9 and IDOL regulatory pathways with improved reduction in cholesterol levels and improve on a potential gene therapeutic approach to treat homozygous familial hypercholesterolemia subjects.

Plasmid-based Sleeping Beauty (SB) transposon vectors were developed and used to deliver genes for low-density lipoprotein and very-low-density lipoprotein receptors (LDLR and VLDLR, respectively) or lacZ reporter into liver of an LDLR-deficient mouse model of familial hypercholesterolemia (FH). SB transposase, SB100x, was used to integrate the therapeutic transposons into mice livers for evaluating the feasibility of the vectors in reducing high blood cholesterol and the progression of atherosclerosis. Hydrodynamic gene delivery of transposon-VLDLR into the livers of the mice resulted in initial 17-19% reductions in plasma cholesterol, and at the later time points, in a significant stabilization of the cholesterol level for the 6.5-month duration of the study compared to the control mice. Transposon-LDLR-treated animals also demonstrated a trend of stabilization in the cholesterol levels in the long term. Vector-treated mice had slightly less lipid accumulation in the liver and reduced aortic atherosclerosis. Clinical chemistry and histological analyses revealed normal liver function and morphology comparable to that of the controls during the follow-up with no safety issues regarding the vector type, transgenes, or the gene transfer method. The study demonstrates the safety and potential benefits of the SB transposon vectors in the treatment of FH.

Familial hypercholesterolemia (FH) is a genetic autosomal dominant disorder caused by an impaired receptor-mediated low-density lipoprotein (LDL) removal from the circulation, mainly due to disruptive autosomal co-dominant mutations in the LDL receptor (LDLr) gene, but also less frequently in the apolipoprotein B100 (APOB) and proprotein convertase subtilisin/kexin type 9 (PCSK9) genes. A rare form of autosomal recessive FH has been also described due to LDLr adaptor protein 1 (LDLRAP1) gene mutations. FH is characterized by very high levels of plasma LDL cholesterol associated with the high incidence of premature atherosclerotic cardiovascular disease (CVD). Despite heterozygous FH (HeFH) patients are still poorly recognized and treated, there is today a large availability of drugs (i.e., statins, ezetimibe and PCSK9 inhibitors) allowing theoretically the normalization of plasma LDL cholesterol levels in this population. Homozygous FH patients (HoFH) have a more severe form of FH, characterized by low responsiveness to the conventional lipid-lowering treatment and often associated with unfavorable prognosis in the young age. Inspired by promising outcomes obtained by orthotopic liver transplantation (OLT), scientists are investigating the possibility of correcting the defective LDLr in these patients by using gene therapy approaches to achieve a novel therapeutic solution with high efficiency. In this article, we tried to review the in vitro, ex vivo, and in vivo attempts conducted to correct FH-causing LDLr gene mutations by using different methods of gene delivery, gene editing, and stem cell manipulation. We also discussed some clinical trials performed in this context.

Background High rates of inadequate health literacy are associated with maladaptive health outcomes in chronic disease including increased mortality and morbidity rates, poor treatment adherence and poor health. Adequate health literacy may be an important factor in the effective treatment and management of familial hypercholesterolemia, and may also be implicated in genetic screening for familial hypercholesterolemia among index cases. The present study examined the prevalence and predictors of health literacy in familial hypercholesterolemia patients attending clinics in seven countries. Design Cross-sectional survey. Methods Consecutive FH patients attending clinics in Australia, Brazil, China, Hong Kong, Malaysia, Taiwan and the UK completed measures of demographic variables (age, gender, household income and highest education level) and a brief three-item health literacy scale. Results Rates of inadequate health literacy were lowest in the UK (7.0%), Australia (10.0%), Hong Kong (15.7%) and Taiwan (18.0%) samples, with higher rates in the Brazil (22.0%), Malaysia (25.0%) and China (37.0%) samples. Income was an independent predictor of health literacy levels, accounting for effects of age. Health literacy was also independently related to China national group membership. Conclusions Findings indicate non-trivial levels of inadequate health literacy in samples of familial hypercholesterolemia patients. Consistent with previous research in chronic illness, inadequate health literacy is related to income as an index of health disparities. Chinese familial hypercholesterolemia patients are more likely to have high rates of inadequate health literacy independent of income. Current findings highlight the imperative of education interventions targeting familial hypercholesterolemia patients with inadequate health literacy.

BACKGROUND:Familial hypercholesterolemia is a monogenic autosomal dominant dyslipidemia characterized by a permanent and isolated increase of cholesterol carried by low-density lipoproteins. The prevalence of its heterozygous form is estimated between 1/500 and 1/250, and in the absence of specific treatment, this form is responsible for an increase by a factor of 13 of the risk of premature coronary artery disease compared to patients non-affected by the disease. OBJECTIVES:To perform an inventory of the knowledge of heterozygous familial hypercholesterolemia in France for physicians involved in the management of the disease. METHODS:A survey was conducted (by phone and internet) among a representative sample of 495 physicians (cardiologists, endocrinologists/diabetologists, gynecologists, general practitioners) who, in parallel, completed 579 patient records. RESULTS:Thirty-two percent (95% CI [27.8; 36.2]) of physicians reported the difference between polygenic hypercholesterolemia and familial hypercholesterolemia. The presence of tendinous xanthomas, a key element of diagnosis, was spontaneously mentioned by 44% (95% CI [34; 54.2]) of cardiologists. Six percent (95% CI [2.2; 12.6]) of them gave a correct estimate of the prevalence of familial hypercholesterolemia. The likelihood of transmission of heterozygous familial hypercholesterolemia, when one parent is affected, was known for 59% (95% CI [48.7; 68.7]) of surveyed cardiologists. A cascade screening was performed systematically by 4% (95% CI [1.1; 9.9]) of them. Eighteen percent (95% CI [11; 26.9]) of cardiologists gave an accurate estimation of cardiovascular risk of heterozygous familial hypercholesterolemia. Fifty-seven percent (95% CI [46.7; 66.8]) of cardiologists admitted being misinformed about the heterozygous familial hypercholesterolemia and 83% (95% CI [74.1; 89.7]) expressed a need for information about this disease. CONCLUSION:The lack of knowledge of heterozygous familial hypercholesterolemia and its associated cardiovascular risk is probably the cause of a diagnostic default leading to inappropriate management of this disease.

Familial hypercholesterolaemia is common in individuals who had a myocardial infarction at a young age. As many as one in 200 people could have heterozygous familial hypercholesterolaemia, and up to one in 300 000 individuals could be homozygous. The phenotypes of heterozygous and homozygous familial hypercholesterolaemia overlap considerably; the response to treatment is also heterogeneous. In this Review, we aim to define a phenotype for severe familial hypercholesterolaemia and identify people at highest risk for cardiovascular disease, based on the concentration of LDL cholesterol in blood and individuals' responsiveness to conventional lipid-lowering treatment. We assess the importance of molecular characterisation and define the role of other cardiovascular risk factors and advanced subclinical coronary atherosclerosis in risk stratification. Individuals with severe familial hypercholesterolaemia might benefit in particular from early and more aggressive cholesterol-lowering treatment (eg, with PCSK9 inhibitors). In addition to better tailored therapy, more precise characterisation of individuals with severe familial hypercholesterolaemia could improve resource use.