The complex molecular genetics of familial hypercholesterolaemia

Genetic variation across and within individuals

Germline variation and somatic mutation are intricately connected and together shape human traits and disease risks. Germline variants are present from conception, but they vary between individuals and accumulate over generations. By contrast, somatic mutations accumulate throughout life in a mosaic manner within an individual due to intrinsic and extrinsic sources of mutations and selection pressures acting on cells. Recent advancements, such as improved detection methods and increased resources for association studies, have drastically expanded our ability to investigate germline and somatic genetic variation and compare underlying mutational processes. A better understanding of the similarities and differences in the types, rates and patterns of germline and somatic variants, as well as their interplay, will help elucidate the mechanisms underlying their distinct yet interlinked roles in human health and biology.

Advancements in risk stratification and management strategies in primary cardiovascular prevention

Atherosclerotic cardiovascular disease (ASCVD) remains a leading cause of morbidity and mortality worldwide, highlighting the urgent need for advancements in risk assessment and management strategies. Although significant progress has been made recently, identifying and managing apparently healthy individuals at a higher risk of developing atherosclerosis and those with subclinical atherosclerosis still poses significant challenges. Traditional risk assessment tools have limitations in accurately predicting future events and fail to encompass the complexity of the atherosclerosis trajectory. In this review, we describe novel approaches in biomarkers, genetics, advanced imaging techniques, and artificial intelligence that have emerged to address this gap. Moreover, polygenic risk scores and imaging modalities such as coronary artery calcium scoring, and coronary computed tomography angiography offer promising avenues for enhancing primary cardiovascular risk stratification and personalised intervention strategies. On the other hand, interventions aiming against atherosclerosis development or promoting plaque regression have gained attention in primary ASCVD prevention. Therefore, the potential role of drugs like statins, ezetimibe, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, omega-3 fatty acids, antihypertensive agents, as well as glucose-lowering and anti-inflammatory drugs are also discussed. Since findings regarding the efficacy of these interventions vary, further research is still required to elucidate their mechanisms of action, optimize treatment regimens, and determine their long-term effects on ASCVD outcomes. In conclusion, advancements in strategies addressing atherosclerosis prevention and plaque regression present promising avenues for enhancing primary ASCVD prevention through personalised approaches tailored to individual risk profiles. Nevertheless, ongoing research efforts are imperative to refine these strategies further and maximise their effectiveness in safeguarding cardiovascular health.

From Atherosclerotic Plaque to Myocardial Infarction-The Leading Cause of Coronary Artery Occlusion

Cardiovascular disease (CVD) constitutes the most common cause of death worldwide. In Europe alone, approximately 4 million people die annually due to CVD. The leading component of CVD leading to mortality is myocardial infarction (MI). MI is classified into several types. Type 1 is associated with atherosclerosis, type 2 results from inadequate oxygen supply to cardiomyocytes, type 3 is defined as sudden cardiac death, while types 4 and 5 are associated with procedures such as percutaneous coronary intervention and coronary artery bypass grafting, respectively. Of particular note is type 1, which is also the most frequently occurring form of MI. Factors predisposing to its occurrence include, among others, high levels of low-density lipoprotein cholesterol (LDL-C) in the blood, cigarette smoking, chronic kidney disease (CKD), diabetes mellitus (DM), hypertension, and familial hypercholesterolaemia (FH). The primary objective of this review is to elucidate the issues with regard to type 1 MI. Our paper delves into, amidst other aspects, its pathogenesis, risk assessment, diagnosis, pharmacotherapy, and interventional treatment options in both acute and long-term conditions.

LDLR variant classification for improved cardiovascular risk prediction in familial hypercholesterolemia

BACKGROUND AND AIMS

Familial hypercholesterolemia (FH) is a genetic disorder marked by high LDL cholesterol and an increased premature coronary artery disease (CAD) risk. Current dichotomous classification of LDL receptor gene (LDLR) variants may inadequately capture patient variability in LDL cholesterol levels and CAD risk. This study assessed a novel approach for determining LDLR variant severity using variant-specific LDL cholesterol percentiles.

METHODS

Participants of the Dutch FH cascade screening program were screened for 456 LDLR variants. For each LDLR variant carrier, a sex- and age-specific LDL cholesterol percentile was derived from the LDL cholesterol level measured at study entry, i.e. generally from the blood drawn for DNA analysis. These percentiles were used to calculate the mean LDL cholesterol percentile for each variant. Based on the variant-specific LDL cholesterol percentiles, carriers were grouped into the following LDL cholesterol strata: <75th, 75th-88th, 88th-92nd, 92nd-96.5th, 96.5th-98th, and ≥98th percentile. Additionally, variants were categorized into class 1 (LDLR deficient) and non-class 1 (often LDLR defective) variants. CAD risk between carriers in the different LDL cholesterol strata and non-carriers was compared using a Cox proportional hazard model.

RESULTS

Out of 35,067 participants, 12,485 (36 %) LDLR variant carriers (mean age 38.0 ± 20.0 years, 47.7 % male) were identified. Carriers had a 5-fold higher CAD risk compared with non-carriers. Hazard ratios for CAD increased gradually from 2.2 (95%CI 0.97-5.0) to 12.0 (95%CI 5.5-24.8) across the LDL cholesterol strata. A 7.3-fold and 3.9-fold increased CAD risk was observed in carriers of class 1 and non-class 1 LDLR variants, respectively.

CONCLUSIONS

This study presents a refined approach for classifying LDLR variants based on their impact on LDL cholesterol levels, allowing for more precise, genotype-specific CAD risk estimation in FH patients compared with traditional methods.

Flavonoids regulate LDLR through different mechanisms tied to their specific structures

Flavonoids, polyphenolic compounds found in plant-based diets, are associated with reduced risk of cardiovascular disease and longevity. These components are reported to reduce plasma levels of low-density lipoprotein (LDL) through an upregulation of the LDL receptor (LDLR), but the mechanism is still largely unknown. In this study, we have systematically screened the effect of 12 flavonoids from six different flavonoid subclasses on the effect on LDLR. This paper provides an in-depth analysis on how these flavonoids affect LDLR regulation and functionality. We found that most but not all of the tested flavonoids increased LDLR mRNA levels. Surprisingly, this increase was attributed to different regulatory mechanisms, such as enhanced LDLR promoter activity, LDLR mRNA stabilization, or LDLR protein stabilization, of which specific effectual parts of the flavonoid molecular structure could be assigned. These types of comparative analysis of various flavonoids enhance clarity and deepen the understanding of how the different structures of flavonoids affect LDLR regulation. Our data offer useful insights that may guide future research in developing therapeutic approaches for cardiovascular health.

Genetic heterogeneity of familial hypercholesterolaemia in two populations from two different countries

BACKGROUND

Familial hypercholesterolemia (FH) is a genetically determined monogenic disorder of predominantly autosomal dominant inheritance. A number of studies on differences in the genetic profile of patients with FH have demonstrated the importance of a more substantive evaluation of genetic features. The aim of this study was to evaluate the genetic profile of patients with clinical FH among Italian and Russian patients.

METHODS

We included 144 Italian and 79 Russian FH patients; clinical diagnosis was based on the same criteria. Patients were divided in: positive to genetic test (one causative variant), inconclusive (only variants of uncertain clinical significance [VUS]), and negative (with likely benign/benign variants, heterozygous variants in LDLRAP1 gene, or without causative variants).

RESULTS

The genetic test was positive in 76.4 % of the Italian patients and in 49.4 % of the Russian patients. The presence of VUS alone was detected in 7.6 % and in 19.0 % (p < 0.001), respectively. Among patients with positive genetic diagnosis, pre-treatment LDL-C levels were higher in the Russian cohort (353.5 ± 111.3 vs. 302.7 ± 52.1 mg/dL, p = 0.009), as well as the percentage of treated patients (53.8 % vs. 14.5 %, p < 0.001) and the prevalence of premature coronary heart disease (12.8 % vs. 3.6 %, p = 0.039). Among patients carrying only VUS, mean pre-treatment LDL-C levels were similar between the cohorts (299.5 ± 68.1 vs. 295.3 ± 46.8 mg/dL, p = 0.863). Among pathogenic/likely pathogenic variants and VUS, only 5 % and 4 % was shared between the two cohorts, respectively.

CONCLUSION

The genetic background of patients clinically diagnosed with FH in two different countries is characterized by high variability.

Dyslipidemia in Adults with Type 2 Diabetes in a Rural Community in Ganadougou, Mali: A Cross-Sectional Study

Dyslipidemia is a disorder where abnormally lipid concentrations circulate in the bloodstream. The disorder is common in type 2 diabetics (T2D) and is linked with T2D comorbidities, particularly cardiovascular disease. Dyslipidemia in T2D is typically characterized by elevated plasma triglyceride and low high-density lipoprotein cholesterol (HDL-C) levels. There is a significant gap in the literature regarding dyslipidemia in rural parts of Africa, where lipid profiles may not be captured through routine surveillance. This study aimed to characterize the prevalence and demo-graphic profile of dyslipidemia in T2D in the rural community of Ganadougou, Mali. We performed a cross-sectional study of 104 subjects with T2D in Ganadougou between November 2021 and March 2022. Demographic and lipid profiles were collected through cross-sectional surveys and serological analyses. The overall prevalence of dyslipidemia in T2D patients was 87.5% (91/104), which did not differ by sex (P = .368). High low-density lipoprotein cholesterol (LDL-C) was the most common lipid abnormality (78.9%, [82/104]). Dyslipidemia was associated with age and hypertension status (P = .013 and.036, respectively). High total and high LDL-C parameters were significantly associated with hypertension (P = .029 and .006, respectively). In low-resource settings such as rural Mali, there is a critical need to improve infrastructure for routine dyslipidemia screening to guide its prevention and intervention approaches. The high rates of dyslipidemia observed in Gandadougou, consistent with concomitant increases in cardiovascular diseases in Africa suggest that lipid profile assessments should be incorporated into routine medical care for T2D patients in African rural settings.

Applicability of Artificial Intelligence in the Field of Clinical Lipidology: A Narrative Review

The development of advanced technologies in artificial intelligence (AI) has expanded its applications across various fields. Machine learning (ML), a subcategory of AI, enables computers to recognize patterns within extensive datasets. Furthermore, deep learning, a specialized form of ML, processes inputs through neural network architectures inspired by biological processes. The field of clinical lipidology has experienced significant growth over the past few years, and recently, it has begun to intersect with AI. Consequently, the purpose of this narrative review is to examine the applications of AI in clinical lipidology. This review evaluates various publications concerning the diagnosis of familial hypercholesterolemia, estimation of low-density lipoprotein cholesterol (LDL-C) levels, prediction of lipid goal attainment, challenges associated with statin use, and the influence of cardiometabolic and dietary factors on the discordance between apolipoprotein B and LDL-C. Given the concerns surrounding AI techniques, such as ethical dilemmas, opacity, limited reproducibility, and methodological constraints, it is prudent to establish a framework that enables the medical community to accurately interpret and utilize these emerging technological tools.

Between hope and reality: treatment of genetic diseases through nucleic acid-based drugs

Rare diseases (RD) affect a small number of people compared to the general population and are mostly genetic in origin. The first clinical signs often appear at birth or in childhood, and patients endure high levels of pain and progressive loss of autonomy frequently associated with short life expectancy. Until recently, the low prevalence of RD and the gatekeeping delay in their diagnosis have long hampered research. The era of nucleic acid (NA)-based therapies has revolutionized the landscape of RD treatment and new hopes arise with the perspectives of disease-modifying drugs development as some NA-based therapies are now entering the clinical stage. Herein, we review NA-based drugs that were approved and are currently under investigation for the treatment of RD. We also discuss the recent structural improvements of NA-based therapeutics and delivery system, which overcome the main limitations in their market expansion and the current approaches that are developed to address the endosomal escape issue. We finally open the discussion on the ethical and societal issues that raise this new technology in terms of regulatory approval and sustainability of production.

Identification of a novel LDLR p.Glu179Met variant in Thai families with familial hypercholesterolemia and response to treatment with PCSK9 inhibitor

Familial hypercholesterolemia (FH) is a genetic disease characterized by elevated LDL-C levels. In this study, two FH probands and 9 family members from two families from northeastern Thailand were tested for LDLR, APOB, and PCSK9 variants by whole-exome sequencing, PCR-HRM, and Sanger sequencing. In silico analysis of LDLR was performed to analyse its structure‒function relationship. A novel variant of LDLR (c.535_536delinsAT, p.Glu179Met) was detected in proband 1 and proband 2 in homozygous and heterozygous forms, respectively. A total of 6 of 9 family members were heterozygous for LDLR p.Glu179Met variant. Compared with proband 2, proband 1 had higher baseline TC and LDL-C levels and a poorer response to lipid-lowering therapy combined with a PCSK9 inhibitor. Multiple sequence alignment showed that LDLR p.Glu179Met was located in a fully conserved region. Homology modelling demonstrated that LDLR p.Glu179Met variant lost one H-bond and a negative charge. In conclusion, a novel LDLR p.Glu179Met variant was identified for the first time in Thai FH patients. This was also the first report of homozygous FH patient in Thailand. Our findings may expand the knowledge of FH-causing variants in Thai population, which is beneficial for cascade screening, genetic counselling, and FH management to prevent coronary artery disease.

Advances in familial hypercholesterolemia

Familial hypercholesterolemia (FH), a semi-dominant genetic disease affecting more than 25 million people worldwide, is associated with severe hypercholesterolemia and premature atherosclerotic cardiovascular disease. Over the last decade, advances in data analysis, screening, diagnosis and cardiovascular risk stratification has significantly improved our ability to deliver precision medicine for these patients. Furthermore, recent updates on guideline recommendations and new therapeutic approaches have also proven to be highly beneficial. It is anticipated that both ongoing and upcoming clinical trials will offer further insights for the care and treatment of FH patients.

Nanoparticles and siRNA: A new era in therapeutics?

Since its discovery in 1998, the use of small interfering RNA (siRNA) has been increasing in biomedical studies because of its ability to very selectively inhibit the expression of any target gene. Thus, siRNAs can be used to generate therapeutic compounds for different diseases, including those that are currently 'undruggable'. This has led siRNA-based therapeutic compounds to break into clinical settings, with them holding the promise to potentially revolutionise therapeutic approaches. To date, the United States Food and Drug Administration (FDA) have approved 5 compounds for treating different diseases including hypercholesterolemia, transthyretin-mediated amyloidosis (which leads to polyneuropathy), hepatic porphyria, and hyperoxaluria. This current article presents an overview of the molecular mechanisms involved in the selective pharmacological actions of siRNA-based compounds. It also describes the ongoing clinical trials of siRNA-based therapeutic compounds for hepatic diseases, pulmonary diseases, atherosclerosis, hypertriglyceridemia, transthyretin-mediated amyloidosis, and hyperoxaluria, kidney diseases, and haemophilia, as well as providing a description of FDA-approved siRNA therapies. Because of space constraints and to provide an otherwise comprehensive review, siRNA-based compounds applied to cancer therapies have been excluded. Finally, we discuss how the use of lipid-based nanoparticles to deliver siRNAs holds promise for selectively targeting mRNA-encoding proteins associated with the genesis of different diseases. Thus, siRNAs can help reduce the cellular levels of these proteins, thereby contributing to disease treatment. As consequence, a marked increase in the number of marketed siRNA-based medicines is expected in the next two decades, which will likely open up a new era of therapeutics.

Evinacumab-dgnb (Evkeeza-REGN1500), A Novel Lipid-Lowering Therapy for Homozygous Familial Hypercholesterolemia

Chronically elevated low-density lipoprotein (LDL) has harmful effects on the vasculature including increased vasoconstriction and the formation of plaques which may rupture, causing coronary heart disease and stroke. In patients with familial hypercholesterolemia, adequate reduction of LDL is especially challenging. Although HMG-CoA reductase inhibitors (statins) are the mainstays for LDL lowering, other treatments such as proprotein convertase subtilisin/kexin type 9 inhibitors, bempedoic acid, incliseran, lomitapide, and apheresis have been employed in an effort to achieve adequate LDL reduction in these patients. Despite these available therapies, many patients with familial hypercholesterolemia do not meet the LDL targets suggested in current guidelines. Evinacumab is a novel lipid-lowering therapy that exerts its LDL-lowering effect through inhibition of angiopoietin-like protein 3 (ANGPTL3). ANGPTL3 inhibits the breakdown of triglyceride-rich lipoproteins, such as very low-density lipoprotein and chylomicrons. By inhibiting ANGPTL3, evinacumab allows these lipoproteins to be degraded, ultimately leading to reductions in LDL, high-density lipoprotein, and triglycerides. Clinical trials have demonstrated evinacumab to be safe and effective in reducing LDL. However, data are lacking regarding its potential to reduce risk of atherosclerotic cardiovascular disease. Evinacumab is generally well tolerated with the primary adverse effects comprising infusion reactions, nasopharyngitis, influenza-like illness, dizziness, rhinorrhea, and nausea. While evinacumab is an interesting therapy, until it is proven to reduce cardiovascular events, its high cost leaves its anticipated role in therapy somewhat ambiguous. In the meantime, it may be a useful therapy for those with homozygous familial hypercholesterolemia.

Lipoprotein (a) is a predictor of non-achievement of LDL-C goals in patients with chronic heart disease

INTRODUCTION AND OBJECTIVES

Lipoprotein (a) [Lp(a)] concentration influences serum low-density lipoprotein cholesterol (LDL-C) levels. How it influences the achievement of LDL-C targets established in the guidelines is not well studied. Our aim was to know the prevalence of elevated Lp(a) levels in patients with coronary artery disease, and to assess its influence on the achievement of LDL-C targets.

METHOD

We conducted a cross-sectional study in a cardiology department in Spain. A total of 870 patients with stable coronary artery disease had their lipid profile determined, including Lp(a). Patients were stratified into 2 groups according to Lp(a)>50mg/dL and Lp(a)≤50mg/dL. The association of Lp(a)>50mg/dL with achievement of LDL-C targets was assessed by logistic regression analysis.

RESULTS

The prevalence of Lp(a)>50mg/dL was 30.8%. Patients with Lp(a)>50mg/dL had higher baseline (142.30±47.54 vs. 130.47±40.75mg/dL; p=0.0001) and current (72.91±26.44 vs. 64.72±25.30mg/dL; p=0.0001), despite the fact that they were treated with more high-potency statins (77.2 vs. 70.9%; p=0.058) and more combination lipid-lowering therapy (37.7 vs. 25.7%; p=0.001). The proportion of patients achieving target LDL-C was lower in those with Lp(a)>50mg/dL. Independent predictors of having elevated Lp(a) levels>50mg/dL were the use of high-potency statins (OR 1.5; 95% CI 1.08-2.14), combination lipid-lowering therapy with ezetimibe (OR 2.0; 95% CI 1.45-2.73) and failure to achieve a LDL-C ≤55mg/dL (OR 2.3; 95% CI 1.63-3.23).

CONCLUSIONS

Elevated Lp(a) levels influence LDL-C levels and hinder the achievement of targets in patients at very high cardiovascular risk. New drugs that act directly on Lp(a) are needed in these patients.

High Lipoprotein(a) May Explain One-Quarter of Clinical Familial Hypercholesterolemia Diagnoses in Danish Lipid Clinics

CONTEXT

Cholesterol carried in lipoprotein(a) adds to measured low-density lipoprotein cholesterol (LDL-C) and may therefore drive some diagnoses of clinical familial hypercholesterolemia (FH).

OBJECTIVE

We investigated plasma lipoprotein(a) in individuals referred to Danish lipid clinics and evaluated the effect of plasma lipoprotein(a) on a diagnosis of FH.

METHODS

Individuals referred to 15 Danish lipid clinics who were suspected of having FH according to nationwide referral criteria were recruited between September 1, 2020 and November 30, 2021. All individuals were classified according to the Dutch Lipid Clinical Network criteria for FH before and after LDL-C was adjusted for 30% cholesterol content in lipoprotein(a). We calculated the fraction of individuals fulfilling a clinical diagnosis of FH partly due to elevated lipoprotein(a).

RESULTS

We included a total of 1166 individuals for analysis, of whom 206 fulfilled a clinical diagnosis of FH. Median lipoprotein(a) was 15 mg/dL (29 nmol/L) in those referred and 28% had lipoprotein(a) greater than or equal to 50 mg/dL (105 nmol/L), while 2% had levels greater than or equal to 180 mg/dL (389 nmol/L). We found that in 27% (55/206) of those fulfilling a clinical diagnosis of FH, this was partly due to high lipoprotein(a).

CONCLUSION

Elevated lipoprotein(a) was common in individuals referred to Danish lipid clinics and in one-quarter of individuals who fulfilled a clinical diagnosis of FH, this was partly due to elevated lipoprotein(a). These findings support the notion that the LPA gene should be considered an important causative gene in patients with clinical FH and further support the importance of measuring lipoprotein(a) when diagnosing FH as well as for stratification of cardiovascular risk.

Cardiovascular disease prevention in heterozygous familial hypercholesterolemia: how important is a healthy diet in the era of long-lasting cholesterol-lowering drug therapies?

PURPOSE OF REVIEW

This review aims to provide an in-depth perspective on the importance of diet for cardiovascular disease (CVD) prevention in heterozygous familial hypercholesterolemia (HeFH).

RECENT FINDINGS

Even though data on diet and CVD prevention in HeFH are limited, the currently available evidence supports its cholesterol-lowering effect and its favorable association with CVD risk on the long-term. However, qualitative evidence from individuals with HeFH suggests that there is a common perception that diet is useless compared to medication, and this misconception serves as a barrier to healthy eating. On the other hand, evidence also suggests that individuals with HeFH are at higher risk of eating disorders compared with unaffected individuals. Family history of premature death and the chronic nature of the disease would be in cause.

SUMMARY

Emphasizing a healthy diet needs to remain at the foundation of CVD prevention in HeFH. Evidence are limited but supportive of the cholesterol-lowering and cardioprotective potential effects of diet. Engaging in conversations about healthy dieting with individuals in HeFH is likely to help prevent misconceptions about diet. Additionally, it could help reduce the risk of eating disorders, which, altogether, is likely to improve overall CVD prevention.

The genetics of autosomal dominant familial hypercholesterolemia

ABSTRACT

Familial hypercholesterolemia (FH) is one of the most common genetic conditions. Affected individuals are unable to metabolize cholesterol due to inherited changes in the low-density lipoprotein (LDL) receptor, which impairs the ability to metabolize cholesterol, resulting in extremely high levels of cholesterol that leads to premature coronary artery disease. Autosomal dominant FH is caused by variants in several genes, which may present as heterozygous FH (less severe) or homozygous FH (more severe). Clinical diagnosis may be more likely when there is a family history of two or more first-degree relatives with total and LDL-cholesterol (LDL-C) level elevations, a child is identified, or the affected individual or close relatives have tendon xanthomas and/or progressive atherosclerosis. This article provides an overview of autosomal dominant FH, including disease prevalence, clinical diagnostic criteria, genetic variants, diagnostic testing, pathognomonic findings, and treatment options. It also shares a brief case, which highlights challenges associated with genetic test interpretation and the importance of including experienced providers in the diagnosis and treatment of this underdiagnosed and often untreated or undertreated genetic condition.

Research Progress in the Clinical Treatment of Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is an autosomal dominant inheritable disease with severe disorders of lipid metabolism. It is mainly marked by increasing levels of plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), xanthoma, corneal arch, and early-onset coronary heart disease (CHD). The prevalence of FH is high, and it is dangerous and clinically underdiagnosed. The clinical treatment for FH includes both pharmacological and non-pharmacological treatment, of which non-pharmacological treatment mainly includes therapeutic lifestyle change and dietary therapy, LDL apheresis, liver transplantation and gene therapy. In recent years, many novel drugs have been developed to treat FH more effectively. In addition, the continuous maturity of non-pharmacological treatment techniques has also brought more hope for the treatment of FH. This paper analyzes the pathogenic mechanism and the progress in clinical treatment of FH. Furthermore, it also summarizes the mechanism and structure-activity relationship of FH therapeutic drugs that have been marketed. In a word, this article provides a reference value for the research and development of FH therapeutic drugs.

Liver-Specific Ionizable Lipid Nanoparticles Mediated Efficient RNA Interference to Clear "Bad Cholesterol"

Background

High-level low-density lipoprotein cholesterol (LDL-C) plays a vital role in the development of atherosclerotic cardiovascular disease. Low-density lipoprotein receptors (LDLRs) are scavengers that bind to LDL-C in the liver. LDLR proteins are regulated by proprotein convertase subtilisin/kexin type 9 (PCSK9), which mediates the degradation of LDLR and adjusts the level of the plasma LDL-C. The low expression of PCSK9 leads to the up-regulation of liver LDLRs and the reduction of plasma LDL-C. Hepatocytes are attractive targets for small interfering RNA (siRNA) delivery to silence Pcsk9 gene, due to their significant role in LDL-C regulation.

Methods

Here, a type of liver-specific ionizable lipid nanoparticles is developed for efficient siRNA delivery. This type of nanoparticles shows high stability, enabling efficient cargo delivery specifically to hepatocytes, and a membrane-active polymer that reversibly masks activity until an acidic environment is reached.

Results

Significantly, the siPcsk9 (siRNA targeting to Pcsk9)-loaded nanoparticles (GLP) could silence 90% of the Pcsk9 mRNA in vitro. In vivo study showed that the improved accumulation of GLP in the liver increased LDLR level by 3.35-fold and decreased plasma LDL-C by 35%.

Conclusion

GLP has shown a powerful effect on reducing LDL-C, thus providing a potential therapy for atherosclerotic cardiovascular disease.

Clinical characteristics associated with elevated levels of lipoprotein(a) in patients with vascular risk

Objectives

Lipoprotein(a) (Lp(a)) is increasingly used in the evaluation of patients with vascular risk due to its association with cardiovascular events. The purpose of this study was to identify the clinical characteristics of patients with elevated levels of Lp(a) attended in an outpatient vascular risk unit.

Methods

An observational, retrospective study was conducted to assess the clinical characteristics of patients with elevated levels of Lp(a) (≥50 mg/dL), as compared to patients with normal values (<50 mg/dL). The sample was composed of 878 patients identified as having a high vascular risk due to a diagnosis of vascular disease, attended in a vascular risk unit between 2021 and 2022.

Results

The highest levels of Lp(a) were independently associated with a higher probability of having a history of peripheral arterial disease (p=0.024), polygenic familial hypercholesterolemia (PH, p=0.030) and combined familial hypercholesterolemia (CFH, p=0.015); and using PCSK9 inhibitor treatment (p=0.029) and combination therapy with statins and ezetimibe (p=0.018). In contrast, there were no significant differences in relation to familial history of early cardiovascular disease (p=0.143) or personal history of cardiovascular disease (p=0.063), which contrasts with other series.

Conclusions

Elevated levels of Lp(a) were associated with a history of peripheral arterial disease, diagnosis of FHP and CFH, and need for more intense lipid-lowering treatments.

Novel Finnish-enriched variants causing severe hypercholesterolemia and their clinical impact on coronary artery disease

BACKGROUND AND AIMS

Severe hypercholesterolemia (LDL-cholesterol ≥ 5 mmol/l) is a major risk factor for coronary artery disease (CAD). The etiology incudes both genetic and nongenetic factors, but persons carrying mutations in known hypercholesterolemia-associated genes are at significantly higher CAD risk than non-carriers. Yet, a significant proportion of mutation carriers remains undetected while the assessment of genetic candidate variants in clinical practice is challenging.

METHODS

To address these challenges, we set out to test the utility of a practical approach to leverage data from a large reference cohort, the FinnGen Study encompassing 356,082 persons with extensive longitudinal health record information, to aid the clinical evaluation of single genetic candidate genes variants detected by exome sequence analysis in a target population of 351 persons with severe hypercholesterolemia.

RESULTS

We identified 23 rare missense mutations in known hypercholesterolemia genes, 3 of which were previously described mutations (LDLR Pro309Lysfs, LDLR Arg595Gln and APOB Arg3527Gln). Subsequent in silico and clinical assessment of the remaining 20 variants pinpointed two likely hypercholesterolemia-associated variants in LDLR (Arg574Leu and Glu626Lys) and one in LDLRAP1 (Arg151Trp). Heterozygous carriers of the novel LDLR and LDLRAP1 variants received statin treatment more often than non-carriers (OR 2.1, p = 1.8e-6 and OR 1.4, p = 0.001) and untreated carriers had higher risk for ischemic heart disease (OR 2.0, p = 0.03 and OR 1.8, p = 0.008).

CONCLUSIONS

Our data elucidate the wide spectrum of genetic variants impacting hypercholesterolemia and demonstrate the utility of a large reference population to assess the heterogeneous impact of candidate gene variants on cardiovascular disease risk.

Características clínicas asociadas a niveles elevados de lipoproteína(a) en pacientes atendidos por riesgo vascular

Objectivos

La lipoproteína(a) (Lp(a)) es cada vez más relevante en la evaluación de pacientes con riesgo vascular debido a su asociación con una mayor incidencia de eventos cardiovasculares. Este estudio tiene como objetivo identificar las características clínicas de los pacientes con niveles elevados de Lp(a) atendidos en consultas externas por riesgo vascular.

Métodos

Estudio observacional retrospectivo en donde se compararon las características clínicas de los pacientes con niveles elevados de Lp(a) (≥50 mg/dL) con la de los pacientes con valores normales (<50 mg/dL), en un total de 878 pacientes atendidos por riesgo o enfermedad vascular durante los años 2021 y 2022.

Resultados

Los valores más elevados de Lp(a) se asociaron de forma independiente con una mayor probabilidad de antecedentes de enfermedad arterial periférica (p=0,024), hipercolesterolemia familiar poligénica (HFP, p=0,030) e hipercolesterolemia familiar combinada (HFC, p=0,015), el tratamiento de inhibidores de PCSK9 (p=0,029) y la combinación de estatinas y ezetimiba (p=0,018). Sin embargo, no se obtuvieron diferencias significativas para las variables antecedentes familiares de enfermedad cardiovascular precoz (p=0,143) ni para antecedentes de enfermedad cardiovascular previa (p=0,063) a diferencia de lo identificado en otras series.

Conclusiones

Los niveles elevados de Lp(a) se asociaron con antecedentes de enfermedad arterial periférica, diagnóstico de HFP y HFC, así como con la necesidad de utilizar tratamientos hipolipemiantes más intensos.

International Atherosclerosis Society guidance for implementing best practice in the care of familial hypercholesterolaemia

This contemporary, international, evidence-informed guidance aims to achieve the greatest good for the greatest number of people with familial hypercholesterolaemia (FH) across different countries. FH, a family of monogenic defects in the hepatic LDL clearance pathway, is a preventable cause of premature coronary artery disease and death. Worldwide, 35 million people have FH, but most remain undiagnosed or undertreated. Current FH care is guided by a useful and diverse group of evidence-based guidelines, with some primarily directed at cholesterol management and some that are country-specific. However, none of these guidelines provides a comprehensive overview of FH care that includes both the lifelong components of clinical practice and strategies for implementation. Therefore, a group of international experts systematically developed this guidance to compile clinical strategies from existing evidence-based guidelines for the detection (screening, diagnosis, genetic testing and counselling) and management (risk stratification, treatment of adults or children with heterozygous or homozygous FH, therapy during pregnancy and use of apheresis) of patients with FH, update evidence-informed clinical recommendations, and develop and integrate consensus-based implementation strategies at the patient, provider and health-care system levels, with the aim of maximizing the potential benefit for at-risk patients and their families worldwide.

Prevalence and factors associated with possible cases of familial hypercholesterolemia in Brazilian adults: a cross-sectional study

This study aimed to estimate the prevalence of possible cases of FH and analyze associated factors in the adult Brazilian population. Cross-sectional study with laboratory data from the Brazilian National Health Survey, with 8521 participants. Possible cases of FH were defined according to the Dutch Lipid Clinic Network criteria. The prevalence and 95% confidence intervals (95% CI) of possible cases of FH were estimated according to sociodemographic variables, lifestyle, diabetes, hypertension, altered tests, treatment and self-rated health. Logistic regression was used to analyze the associations. The prevalence of possible cases of FH was 0.96%, higher in women, between 45 and 59 years, white race/skin color and others, less education, people with diabetes, hypertension and total cholesterol ≥ 310 mg/dL. The presence of FH was positively associated with regular self-rated health (OR 1.96; 95% CI 0.99-3.84), poor/very poor (OR 3.02; 95% CI 1.30-7.03) and negatively with black race/skin color (OR 0.10; 95% CI 0.02-0.46) and complete elementary school, incomplete high school (OR 0.47; 95% CI 0.23-0.98) and complete high school and more (OR 0.45; 95% CI 0.21-0.95). FH affects 1:104 Brazilian adults, these findings contribute to understanding the burden of disease in Brazil. Due to the scarcity of studies on FH in low- and middle-income countries, further studies are desirable.

LDLR and PCSK9 3´UTR variants and their putative effects on microRNA molecular interactions in familial hypercholesterolemia: a computational approach

BACKGROUND

Familial hypercholesterolemia (FH) is caused by pathogenic variants in low-density lipoprotein (LDL) receptor (LDLR) or its associated genes, including apolipoprotein B (APOB), proprotein convertase subtilisin/kexin type 9 (PCSK9), and LDLR adaptor protein 1 (LDLRAP1). However, approximately 40% of the FH patients clinically diagnosed (based on FH phenotypes) may not carry a causal variant in a FH-related gene. Variants located at 3' untranslated region (UTR) of FH-related genes could elucidate mechanisms involved in FH pathogenesis. This study used a computational approach to assess the effects of 3'UTR variants in FH-related genes on miRNAs molecular interactions and to explore the association of these variants with molecular diagnosis of FH.

METHODS AND RESULTS

Exons and regulatory regions of FH-related genes were sequenced in 83 FH patients using an exon-target gene sequencing strategy. In silico prediction tools were used to study the effects of 3´UTR variants on interactions between miRNAs and target mRNAs. Pathogenic variants in FH-related genes (molecular diagnosis) were detected in 44.6% FH patients. Among 59 3'UTR variants identified, LDLR rs5742911 and PCSK9 rs17111557 were associated with molecular diagnosis of FH, whereas LDLR rs7258146 and rs7254521 and LDLRAP1 rs397860393 had an opposite effect (p < 0.05). 3´UTR variants in LDLR (rs5742911, rs7258146, rs7254521) and PCSK9 (rs17111557) disrupt interactions with several miRNAs, and more stable bindings were found with LDLR (miR-4435, miR-509-3 and miR-502) and PCSK9 (miR-4796).

CONCLUSION

LDLR and PCSK9 3´UTR variants disturb miRNA:mRNA interactions that could affect gene expression and are potentially associated with molecular diagnosis of FH.

Predictive Modeling and Structure Analysis of Genetic Variants in Familial Hypercholesterolemia: Implications for Diagnosis and Protein Interaction Studies

PURPOSE OF REVIEW

Familial hypercholesterolemia (FH) is a hereditary condition characterized by elevated levels of low-density lipoprotein cholesterol (LDL-C), which increases the risk of cardiovascular disease if left untreated. This review aims to discuss the role of bioinformatics tools in evaluating the pathogenicity of missense variants associated with FH. Specifically, it highlights the use of predictive models based on protein sequence, structure, evolutionary conservation, and other relevant features in identifying genetic variants within LDLR, APOB, and PCSK9 genes that contribute to FH.

RECENT FINDINGS

In recent years, various bioinformatics tools have emerged as valuable resources for analyzing missense variants in FH-related genes. Tools such as REVEL, Varity, and CADD use diverse computational approaches to predict the impact of genetic variants on protein function. These tools consider factors such as sequence conservation, structural alterations, and receptor binding to aid in interpreting the pathogenicity of identified missense variants. While these predictive models offer valuable insights, the accuracy of predictions can vary, especially for proteins with unique characteristics that might not be well represented in the databases used for training. This review emphasizes the significance of utilizing bioinformatics tools for assessing the pathogenicity of FH-associated missense variants. Despite their contributions, a definitive diagnosis of a genetic variant necessitates functional validation through in vitro characterization or cascade screening. This step ensures the precise identification of FH-related variants, leading to more accurate diagnoses. Integrating genetic data with reliable bioinformatics predictions and functional validation can enhance our understanding of the genetic basis of FH, enabling improved diagnosis, risk stratification, and personalized treatment for affected individuals. The comprehensive approach outlined in this review promises to advance the management of this inherited disorder, potentially leading to better health outcomes for those affected by FH.

Long-term efficacy and safety of lerodalcibep in heterozygous familial hypercholesterolaemia: the LIBerate-HeFH trial

BACKGROUND AND AIMS

Lerodalcibep, a novel small recombinant fusion protein of a proprotein convertase subtilisin/kexin type 9 gene-binding domain (adnectin) and human serum albumin, demonstrated highly effective low-density lipoprotein cholesterol (LDL-C) reduction with monthly 300 mg in 1.2 mL subcutaneous dosing in Phase 2. In this global Phase 3 trial, the safety and efficacy of lerodalcibep were evaluated in heterozygous familial hypercholesterolaemia patients requiring additional LDL-C lowering.

METHODS

Patients were randomized 2:1 to monthly subcutaneous injections of either lerodalcibep 300 mg or placebo for 24 weeks. The primary efficacy endpoints were the per cent change from baseline in LDL-C at Week 24 and the mean of Weeks 22 and 24.

RESULTS

In 478 randomized subjects [mean age (range); 53 (18-80) years, 51.7% female, mean (SD) baseline LDL-C 3.88 (1.66) mmol/L], lerodalcibep reduced LDL-C, compared with placebo by an absolute amount of 2.08 (0.11) mmol/L [LS mean (SE); 95% confidence interval -2.30 to -1.87] with a percentage difference of -58.61 (3.25)% at Week 24 and by 2.28 (0.10) mmol/L (95% confidence interval -2.47 to -2.09) with a percentage difference of -65.0 (2.87)% at the mean of Weeks 22 and 24 (P < .0001 for all). With lerodalcibep, 68% of subjects achieved both a reduction in LDL-C ≥ 50% and the recommended European Society of Cardiology LDL-C targets during the study. Except for mild injection site reactions, treatment-emergent adverse events were similar between lerodalcibep and placebo.

CONCLUSIONS

Lerodalcibep, a novel anti-proprotein convertase subtilisin/kexin type 9 gene small binding protein dosed monthly as an alternative to monoclonal antibodies, significantly reduced LDL-C in subjects with heterozygous familial hypercholesterolaemia with a safety profile similar to placebo.

Relationship between lifestyle habits and cardiovascular risk factors in familial hypercholesterolemia

BACKGROUND AND AIM

Little is known about the cardioprotective potential of a healthy lifestyle in familial hypercholesterolemia (FH). The objective of this study was to evaluate the relationship between lifestyle and cardiovascular risk factors in adults with FH.

METHODS AND RESULTS

This cross-sectional study leveraged data from the CARTaGENE Quebec population-based cohort (Canada). Participants with FH were identified using the validated Simplified Canadian Definition for FH. A healthy lifestyle score (HLS), ranging from 0 to 5, was calculated per adherence to 5 lifestyle habits: 1) not smoking; 2) being physically active (≥150 min/week of moderate or vigorous physical activity); 3) eating a healthy diet (Alternate Healthy Eating Index ≥50%); 4) having a light to moderate alcohol consumption (men: 1-30 g/day; women: 1-15 g/day); and 5) sleeping 7-8 h/day. Among the 122 included individuals (women, n = 78; men, n = 44; mean age ± SD: 57.3 ± 6.7 years), 92 (75.4%) had a HLS ≤3/5, while only 5 (4.1%) had a HLS of 5/5. After adjustments for sex, age, body mass index, and lipid-lowering medication use, we found no evidence of an association between the HLS and concentrations of LDL-cholesterol (β = 0.04, 95% CI = -0.08, 0.15 mmol/L; P = 0.54). However, the HLS was favorably associated with HbA1c levels (β = -0.07, 95% CI = -0.13, -0.01%; P = 0.02), and statistical trends suggested favorable associations with HDL-cholesterol (β = 0.06, 95% CI = -0.02, 0.14 mmol/L; P = 0.06) and waist circumference (β = -2.22, 95% CI = -4.62, 0.17 cm; P = 0.07).

CONCLUSION

This study suggests that a healthy lifestyle is favorably associated with CVD risk factors in adults with FH.

Possible explanations for the common clinical familial hypercholesterolemia phenotypes in the Faroe Islands

BACKGROUND

The prevalence of clinical familial hypercholesterolemia (FH) is very high in the Faroe Islands, but the possible causes are unknown.

OBJECTIVES

We aimed to describe potential genetic causes of FH in the Faroe Islands and to investigate whether levels of lipoprotein(a) and measures of dietary habits were associated with clinical FH in the Faroe Islands.

METHODS

In this case-control study, we identified potential clinical FH cases aged 18-75 years registered within a nationwide clinical laboratory database in the Faroe Islands and invited them for diagnostic evaluation according to clinical FH scoring systems. Controls were identified in the background population. Lipoprotein(a) was measured in plasma, while the fatty acid composition was determined in adipose tissue. The habitual diet of the participants was assessed using a food frequency questionnaire. Genetic testing for FH and polygenic variants was performed in a selection of clinical FH cases.

RESULTS

A total of 121 clinical FH cases and 123 age- and sex-matched controls were recruited. We found a very low frequency of monogenic FH (2.5%), but a high level of polygenic FH (63%) in those genetically tested (67%). High levels of plasma lipoprotein(a) were associated with high odds of clinical FH. Clinical FH cases had a lower intake of saturated fatty acids (SFAs) measured by a high fat-score and a lower content of SFAs in adipose tissue compared with controls.

CONCLUSION

The high prevalence of FH in the Faroe Islands may be due to polygenic causes of hypercholesterolemia and to a lesser extent other genetic factors and elevated plasma lipoprotein(a) levels.

Barriers and shortcomings in access to cardiovascular management and prevention for familial hypercholesterolemia during the COVID-19 pandemic

Familial hypercholesterolemia (FH) is a hereditary condition caused by mutations in the lipid pathway. The goal in managing FH is to reduce circulating low-density lipoprotein cholesterol and, therefore, reduce the risk of developing atherosclerotic cardiovascular disease (ASCVD). Because FH patients were considered high risk groups due to an increased susceptible for contracting COVID-19 infection, we hypothesized whether the effects of the pandemic hindered access to cardiovascular care. In this review, we conducted a literature search in databases Pubmed/Medline and ScienceDirect. We included a comprehensive analysis of findings from articles in English related and summarized the effects of the pandemic on cardiovascular care through direct and indirect effects. During the COVID-19 pandemic, FH patients presented with worse outcomes and prognosis, especially those that have suffered from early ASCVD. This caused avoidance in seeking care due to fear of transmission. The pandemic severely impacted consultations with lipidologists and cardiologists, causing a decline in lipid profile evaluations. Low socioeconomic communities and ethnic minorities were hit the hardest with job displacements and lacked healthcare coverage respectively, leading to treatment nonadherence. Lock-down restrictions promoted sedentary lifestyles and intake of fatty meals, but it is unclear whether these factors attenuated cardiovascular risk in FH. To prevent early atherogenesis in FH patients, universal screening programs, telemedicine, and lifestyle interventions are important recommendations that could improve outcomes in FH patients. However, the need to research in depth on the disproportionate impact within different subgroups should be the forefront of FH research.

High-Throughput Microscopy Characterization of Rare LDLR Variants

Familial hypercholesterolemia (FH) is the most common inherited life-threatening disorder of lipid metabolism. Early diagnosis and treatment are the key to reduce the cumulative life-long cardiovascular burden of patients with FH. The high number of LDLR variants described as variants of unknown significance is the largest obstacle to achieve a definitive FH diagnosis. This study established a time- and cost-effective high-throughput cell-based assay to functionally profile LDLR variants, which allowed us to discriminate disruptive rare variants from silent ones. This work generated a valuable resource for systematic functional characterization of LDLR variants solving 1 of the major issues to achieve a definitive FH diagnosis.

In vitro assessment of the pathogenicity of the LDLR c.2160delC variant in familial hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia (FH) is an inherited disorder with markedly elevated low-density lipoprotein cholesterol (LDL-C) and premature atherosclerotic cardiovascular disease. Although many mutations have been reported in FH, only a few have been identified as pathogenic mutations. This study aimed to confirm the pathogenicity of the LDL receptor (LDLR) c.2160delC variant in FH.

METHODS

In this study, the proband and her family members were systematically investigated, and a pedigree map was drawn. High-throughput whole-exome sequencing was used to explore the variants in this family. Next, quantitative polymerase chain reaction (qPCR), western blot (WB) assays, and flow cytometry were conducted to detect the effect of the LDLR c.2160delC variant on its expression. The LDL uptake capacity and cell localization of LDLR variants were analyzed by confocal microscopy.

RESULTS

According to Dutch Lipid Clinic Network (DLCN) diagnostic criteria, three FH patients were identified with the LDLR c.2160delC variant in this family. An in-silico analysis suggested that the deletion mutation at the 2160 site of LDLR causes a termination mutation. The results of qPCR and WB verified that the LDLR c.2160delC variant led to early termination of LDLR gene transcription. Furthermore, the LDLR c.2160delC variant caused LDLR to accumulate in the endoplasmic reticulum, preventing it from reaching the cell surface and internalizing LDL.

CONCLUSIONS

The LDLR c.2160delC variant is a terminating mutation that plays a pathogenic role in FH.

Genomic Innovation in Early Life Cardiovascular Disease Prevention and Treatment

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality globally. Although CVD events do not typically manifest until older adulthood, CVD develops gradually across the life-course, beginning with the elevation of risk factors observed as early as childhood or adolescence and the emergence of subclinical disease that can occur in young adulthood or midlife. Genomic background, which is determined at zygote formation, is among the earliest risk factors for CVD. With major advances in molecular technology, including the emergence of gene-editing techniques, along with deep whole-genome sequencing and high-throughput array-based genotyping, scientists now have the opportunity to not only discover genomic mechanisms underlying CVD but use this knowledge for the life-course prevention and treatment of these conditions. The current review focuses on innovations in the field of genomics and their applications to monogenic and polygenic CVD prevention and treatment. With respect to monogenic CVD, we discuss how the emergence of whole-genome sequencing technology has accelerated the discovery of disease-causing variants, allowing comprehensive screening and early, aggressive CVD mitigation strategies in patients and their families. We further describe advances in gene editing technology, which might soon make possible cures for CVD conditions once thought untreatable. In relation to polygenic CVD, we focus on recent innovations that leverage findings of genome-wide association studies to identify druggable gene targets and develop predictive genomic models of disease, which are already facilitating breakthroughs in the life-course treatment and prevention of CVD. Gaps in current research and future directions of genomics studies are also discussed. In aggregate, we hope to underline the value of leveraging genomics and broader multiomics information for characterizing CVD conditions, work which promises to expand precision approaches for the life-course prevention and treatment of CVD.

Genetic Testing for Familial Hypercholesterolemia in a Pediatric Group: A Romanian Showcase

Familial hypercholesterolemia (FH) is a genetic disease marked by high levels of LDL-cholesterol. This condition has long-term clinical implications, such as cardiovascular events, that are evident during adult life. Here, we report on a single-center cross-sectional showcase study of genetic testing for FH in a Romanian pediatric group. Genetic testing for FH was performed on 20 Romanian pediatric patients, 10 boys and 10 girls, admitted with LDL-cholesterol levels over 130 mg/mL to the National Institute for Mother and Child Health "Alesssandrescu-Rusescu" in 2020. Genetic testing was performed using the Illumina TruSight Cardio panel. We identified pathogenic/likely pathogenic variants that could explain the phenotype in 5/20 cases. The involved genes were LDLR and APOB. Clinical signs that suggest the diagnosis of FH are scarce for the pediatric patient, although it can be diagnosed early during childhood by lipid panel screening. Prevention could prove lifesaving for some of these patients.

LDLR gene's promoter region hypermethylation in patients with familial hypercholesterolemia

Familial hypercholesterolemia (FH) is characterized by high low-density lipoprotein cholesterol (LDL-C) levels and a high risk of early coronary heart disease. Structural alterations in the LDLR, APOB, and PCSK9 genes were not found in 20-40% of patients diagnosed using the Dutch Lipid Clinic Network (DCLN) criteria. We hypothesized that methylation in canonical genes could explain the origin of the phenotype in these patients. This study included 62 DNA samples from patients with a clinical diagnosis of FH according to the DCLN criteria, who previously tested negative for structural alterations in the canonical genes, and 47 DNA samples from patients with normal blood lipids (control group). All DNA samples were tested for methylation in the CpG islands of the three genes. The prevalence of FH relative to each gene was determined in both groups and the respective prevalence ratios (PRs) were calculated. The methylation analysis of APOB and PCSK9 was negative in both groups, showing no relationship between methylation in these genes and the FH phenotype. As the LDLR gene has two CpG islands, we analyzed each island separately. The analysis of LDLR-island1 showed PR = 0.982 (CI 0.33-2.95; χ² = 0.001; p = 0.973), also suggesting no relationship between methylation and the FH phenotype. Analysis of LDLR-island2 showed a PR of 4.12 (CI 1.43-11.88; χ² = 13,921; p = 0.00019), indicating a possible association between methylation on this island and the FH phenotype.

Prevalence of familial hypercholesterolemia and its association with coronary artery disease: A Chinese cohort study

Background

Familial hypercholesterolemia (FH) is underrecognized, and its association with coronary artery disease (CAD) remains limited, especially in China. We aimed to investigate the prevalence of FH and its relationship with CAD in a large Chinese cohort.

Methods

FH was defined using the Make Early Diagnosis to Prevent Early Death (MEDPED) criteria. The crude and age-sex standardized prevalence of FH were calculated based on surveys of the Prediction for Atherosclerotic Cardiovascular Disease Risk in China (China-PAR) project during 2007-2008. The associations of FH with incident CAD and its major subtypes were estimated with the cohort-stratified multivariate Cox proportional hazard models based on the data from the baseline to the last follow-up (2018-2020).

Results

Among 98,885 included participants, 190 participants were defined as FH. Crude and age-sex standardized prevalence and 95% confidence interval (CI) of FH were 0.19% (0.17%-0.22%) and 0.13% (0.10%-0.16%), respectively. The prevalence varied across age groups and peaked in the group of 60-<70 years (0.28%), and the peak prevalence (0.18%) in males was earlier, yet lower than the peak crude prevalence in females (0.41%). During a mean follow-up of 10.7 years, 2493 cases of incident CAD were identified. After multivariate adjustment, FH patients had a 2.03-fold greater risk of developing CAD compared to non-FH participants.

Conclusions

The prevalence of FH was estimated to be 0.19% in the participants, and it was associated with an elevated risk of incident CAD. Our study suggests that early screening of FH has certain public health significance for the prevention of CAD.

Systematic elucidation of genetic mechanisms underlying cholesterol uptake

Genetic variation contributes greatly to LDL cholesterol (LDL-C) levels and coronary artery disease risk. By combining analysis of rare coding variants from the UK Biobank and genome-scale CRISPR-Cas9 knockout and activation screening, we substantially improve the identification of genes whose disruption alters serum LDL-C levels. We identify 21 genes in which rare coding variants significantly alter LDL-C levels at least partially through altered LDL-C uptake. We use co-essentiality-based gene module analysis to show that dysfunction of the RAB10 vesicle transport pathway leads to hypercholesterolemia in humans and mice by impairing surface LDL receptor levels. Further, we demonstrate that loss of function of OTX2 leads to robust reduction in serum LDL-C levels in mice and humans by increasing cellular LDL-C uptake. Altogether, we present an integrated approach that improves our understanding of the genetic regulators of LDL-C levels and provides a roadmap for further efforts to dissect complex human disease genetics.

2023 Update on European Atherosclerosis Society Consensus Statement on Homozygous Familial Hypercholesterolaemia: new treatments and clinical guidance

This 2023 statement updates clinical guidance for homozygous familial hypercholesterolaemia (HoFH), explains the genetic complexity, and provides pragmatic recommendations to address inequities in HoFH care worldwide. Key strengths include updated criteria for the clinical diagnosis of HoFH and the recommendation to prioritize phenotypic features over genotype. Thus, a low-density lipoprotein cholesterol (LDL-C) >10 mmol/L (>400 mg/dL) is suggestive of HoFH and warrants further evaluation. The statement also provides state-of-the art discussion and guidance to clinicians for interpreting the results of genetic testing and for family planning and pregnancy. Therapeutic decisions are based on the LDL-C level. Combination LDL-C-lowering therapy-both pharmacologic intervention and lipoprotein apheresis (LA)-is foundational. Addition of novel, efficacious therapies (i.e. inhibitors of proprotein convertase subtilisin/kexin type 9, followed by evinacumab and/or lomitapide) offers potential to attain LDL-C goal or reduce the need for LA. To improve HoFH care around the world, the statement recommends the creation of national screening programmes, education to improve awareness, and management guidelines that account for the local realities of care, including access to specialist centres, treatments, and cost. This updated statement provides guidance that is crucial to early diagnosis, better care, and improved cardiovascular health for patients with HoFH worldwide.

Dynamics of the personalities of PCSK9 on missense variants (rs505151 and rs562556) from elderly cohort studies in Brazil

The Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) promotes the degradation of the low-density lipoprotein receptors (LDLR). Gain-of-function (GOF) variants of PCSK9 significantly affects lipid metabolism leading to coronary artery disease (CAD), owing to the raising the plasma low-density lipoprotein (LDL). Considering the public health matter, large-scale genomic studies have been conducted worldwide to provide the genetic architecture of populations for the implementation of precision medicine actions. Nevertheless, despite the advances in genomic studies, non-European populations are still underrepresented in public genomic data banks. Despite this, we found two high-frequency variants (rs505151 and rs562556) in the ABraOM databank (Brazilian genomic variants) from a cohort SABE study conducted in the largest city of Brazil, São Paulo. Here, we assessed the structural and dynamical features of these variants against WT through a molecular dynamics study. We sought fundamental dynamical interdomain relations through Perturb Response Scanning (PRS) and we found an interesting change of dynamical relation between prodomain and Cysteine-Histidine-Rich-Domain (CHRD) in the variants. The results highlight the pivotal role of prodomain in the PCSK9 dynamic and the implications for the development of new drugs depending on patient group genotype.

Does low-density lipoprotein fully explain atherosclerotic risk in familial hypercholesterolemia?

PURPOSE OF REVIEW

Familial hypercholesterolemia (FH) is a monogenic disorder of elevated low-density lipoprotein cholesterol (LDL-C) from birth leading to increased risk for atherosclerotic cardiovascular disease. However, not all carriers of FH variants display an FH phenotype. Despite this fact, FH variants confer increased risk for atherosclerotic disease in population cohorts. An important question to consider is whether measurements of LDL-C can fully account for this risk.

RECENT FINDINGS

The atherosclerotic risk associated with FH variants is independent of observed adult LDL-C levels. Modeling adult longitudinal LDL-C accounts for more of this risk compared to using a single measurement. Still, even when adjusting for observed longitudinal LDL-C in adult cohorts, FH variant carriers are at increased risk for coronary artery disease. Genetic analyses, observational studies, and clinical trials all suggest that cumulative LDL-C is a critical driver of cardiovascular risk that may not be fully appreciated by routine LDL-C measurements in adulthood. As such, FH variants confer risk independent of adult LDL-C because these variants increase cumulative LDL-C exposure starting from birth.

SUMMARY

Both research and clinical practice focus on LDL-C measurements in adults, but measurements during adulthood do not reflect lifelong cumulative exposure to LDL-C. Genetic assessments may compliment clinical assessments by better identifying patients who have experienced greater longitudinal LDL-C exposure.

Risk factors for cardiovascular events in patients with heterozygous familial hypercholesterolaemia: protocol for a systematic review

INTRODUCTION

Heterozygous familial hypercholesterolaemia (heFH) is the most common monogenic cause of premature atherosclerotic cardiovascular disease. The precise diagnosis of heFH is established by genetic testing. This systematic review will investigate the risk factors that predict cardiovascular events in patients with a genetic diagnosis of heFH.

METHODS AND ANALYSIS

Our literature search will cover publications from database inception until June 2023. We will undertake a search of CINAHL (trial), clinicalKey, Cochrane Library, DynaMed, Embase, Espacenet, Experiments (trial), Fisterra, ÍnDICEs CSIC, LILACS, LISTA, Medline, Micromedex, NEJM Resident 360, OpenDissertations, PEDro, Trip Database, PubPsych, Scopus, TESEO, UpToDate, Web of Science and the grey literature for eligible studies. We will screen the title, abstract and full-text papers for potential inclusion and assess the risk of bias. We will employ the Cochrane tool for randomised controlled trials and non-randomised clinical studies and the Newcastle-Ottawa Scale for assessing the risk of bias in observational studies. We will include full-text peer-reviewed publications, reports of a cohort/registry, case-control and cross-sectional studies, case report/series and surveys related to adults (≥18 years of age) with a genetic diagnostic heFH. The language of the searched studies will be restricted to English or Spanish. The Grading of Recommendations, Assessment, Development and Evaluation approach will be used to assess the quality of the evidence. Based on the data available, the authors will determine whether the data can be pooled in meta-analyses.

ETHICS AND DISSEMINATION

All data will be extracted from published literature. Hence, ethical approval and patient informed consent are not required. The findings of the systematic review will be submitted for publication in a peer-reviewed journal and presentation at international conferences.

PROSPERO REGISTRATION NUMBER

CRD42022304273.

Development of LXR inverse agonists to treat MAFLD, NASH, and other metabolic diseases

Activation of LXR activity by synthetic agonists has been the focus of many drug discovery efforts with a focus on treatment of dyslipidemia and atherosclerosis. Many agonists have been developed, but all have been hindered due to their ability to efficaciously stimulate de novo lipogenesis. Here, we review the development of LXR inverse agonists that were originally optimized for their ability to enable recruitment of corepressors leading to silencing of genes that drive de novo lipogenesis. Such compounds have efficacy in animal models of MAFLD, dyslipidemia, and cancer. Several classes of LXR inverse agonists have been identified and one is now in clinical trials for treatment of severe dyslipidemia.

Biomedical consequences of elevated cholesterol-containing lipoproteins and apolipoproteins on cardiovascular and non-cardiovascular outcomes

BACKGROUND

Higher concentrations of cholesterol-containing low-density lipoprotein (LDL-C) increase the risk of cardiovascular disease (CVD). The association of LDL-C with non-CVD traits remains unclear, as are the possible independent contributions of other cholesterol-containing lipoproteins and apolipoproteins.

METHODS

Nuclear magnetic resonance spectroscopy was used to measure the cholesterol content of high density (HDL-C), very low-density (VLDL-C), intermediate-density (IDL-C), as well as low-density lipoprotein fractions, the apolipoproteins Apo-A1 and Apo-B, as well as total triglycerides (TG), remnant-cholesterol (Rem-Chol) and total cholesterol (TC). The causal effects of these exposures were assessed against 33 outcomes using univariable and multivariable Mendelian randomization (MR).

RESULTS

The majority of cholesterol containing lipoproteins and apolipoproteins affect coronary heart disease (CHD), carotid intima-media thickness, carotid plaque, C-reactive protein (CRP) and blood pressure. Multivariable MR indicated that many of these effects act independently of HDL-C, LDL-C and TG, the most frequently measured lipid fractions. Higher concentrations of TG, VLDL-C, Rem-Chol and Apo-B increased heart failure (HF) risk; often independently of LDL-C, HDL-C or TG. Finally, a subset of these exposures associated with non-CVD traits such as Alzheimer's disease (AD: HDL-C, LDL-C, IDL-C, Apo-B), type 2 diabetes (T2DM: VLDL-C, IDL-C, LDL-C), and inflammatory bowel disease (IBD: LDL-C, IDL-C).

CONCLUSIONS

The cholesterol content of a wide range of lipoprotein and apolipoproteins associate with measures of atherosclerosis, blood pressure, CRP, and CHD, with a subset affecting HF, T2DM, AD and IBD risk. Many of the observed effects appear to act independently of LDL-C, HDL-C, and TG, supporting the targeting of lipid fractions beyond LDL-C for disease prevention.

The longitudinal triglyceride phenotype in heterozygotes with LPL pathogenic variants

BACKGROUND

Biallelic pathogenic variants in lipoprotein lipase (LPL) cause familial chylomicronemia syndrome with severe hypertriglyceridemia (HTG), defined as plasma triglycerides (TG) > 10 mmol/L (> 885 mg/dL). TG levels in individuals with one copy of a pathogenic LPL gene variant is less familiar; some assume that the phenotype is intermediate between homozygotes and controls.

OBJECTIVE

We undertook an evaluation of the longitudinal TG phenotype of individuals heterozygous for pathogenic LPL variants.

METHODS

Medically stable outpatients were evaluated based on having: (1) a single copy of a rare pathogenic LPL variant; and (2) serial fasting TG measurements obtained over > 1.5 years of follow-up.

RESULTS

Fifteen patients with a single pathogenic LPL variant were followed for a mean of 10.3 years (range 1.5 to 30.3 years). TG levels varied widely both within and between patients. One patient had normal TG levels < 2.0 mmol/L (< 175 mg/dL) continuously, while four patients had at least one normal TG level. Most patients fluctuated between mild-to-moderate and severe HTG: five patients had only mild-to-moderate HTG, with TG levels ranging from 2.0 to 9.9 mmol/L (175 to 885 mg/dL), while 6 patients had at least one instance of severe HTG. Of the 203 total TG measurements from these patients, 14.8%, 67.0% and 18.2% were in the normal, mild-to-moderate and severe HTG ranges, respectively.

CONCLUSION

The heterozygous LPL deficient phenotype is highly variable both within and between patients. Heterozygosity confers susceptibility to a wide range of TG phenotypes, with severity likely depending on secondary factors.

Analysis of Clinical and Biochemical Characteristics of Patients With Genetically Confirmed Familial Hypercholesterolemia in Russian North Western District Residents

Aim      To compare results of clinical, laboratory, and genetic examination of patients with familial hypercholesterolemia (FHC).

Material and methods  112 patients aged 40.2±17.9 years (49 men) were examined. The gene of low-density lipoprotein receptor (LDLR) was analyzed and evaluated using the Dutch Lipid Clinic Network (DLCN) criterion of lipid score ≥6. The LDLR gene mutation was searched for using the conformational polymorphism analysis followed by sequencing of the DNA of isolated LDLR gene exons.

Results Mean variables of the blood lipid profile were total cholesterol (C), 10.12±2.32 mmol/l, LDL-C, 7.72±2.3 mmol/l. Corneal arcus was observed in 15 % of patients, tendon xanthomas in 31.8 %, and xanthelasma palpebrarum in 5.3 %. The types of LDLR gene mutations included missense mutations (42.8 %), mutations causing a premature termination of protein synthesis (41.1 %), and frameshift mutations (16.1 %). In the presence of a mutation in exon 4, patients with IHD compared to patients with no IHD had significantly higher levels of total C (10.88±2.08 mmol/l vs. 8.74±1.57 mmol/l, respectively, р=0.001) and LDL-C (8.60±2.14 mmol/l vs. 6.62±1.79 mmol/l, respectively, р=0.005). Patients with IHD compared to patients with no IHD and a mutation in LDLR gene exon 9 had only a higher LDL-C level (8.96±1.53 mmol/l vs. 6.92±1.59 mmol/l, respectively, р=0.022). A differentiated comparison of IHD patients using a logistic regression depending on the identified type of LDLR gene mutation produced formulas for calculating the odds ratio of IHD and myocardial infarction (MI) with adjustments for the patient’s age and baseline LDL.

Conclusion      The detection rate of the LDLR gene mutations was 42.8 % for missense mutations, 41.1 % for mutations causing a premature termination of protein synthesis, and 16.1 % for frameshift mutations. Blood lipid profiles did not differ between patients from different cities and with different types of LDLR gene mutations. Blood lipid profiles were different in IHD patients depending on the mutation type.

The advantages and pitfalls of genetic analysis in the diagnosis and management of lipid disorders

The increasing affordability of and access to next-generation DNA sequencing has increased the feasibility of incorporating genetic analysis into the diagnostic pathway for dyslipidaemia. But should genetic diagnosis be used routinely? DNA testing for any medical condition has potential benefits and pitfalls. For dyslipidaemias, the overall balance of advantages versus drawbacks differs according to the main lipid disturbance. For instance, some patients with severely elevated low-density lipoprotein cholesterol levels have a monogenic disorder, namely heterozygous familial hypercholesterolaemia. In these patients, DNA diagnosis can be definitive, in turn yielding several benefits for patient care that tend to outweigh any potential disadvantages. In contrast, hypertriglyceridaemia is almost always a polygenic condition without a discrete monogenic basis, except for ultrarare monogenic familial chylomicronaemia syndrome. Genetic testing in patients with hypertriglyceridaemia is therefore predominantly non-definitive and evidence for benefit is presently lacking. Here we consider advantages and limitations of genetic testing in dyslipidaemias.

Generalidades del metabolismo de los lípidos y del manejo de la de los lípidos y del manejo de la hipercolesterolemia

Introducción: los lípidos hacen parte fundamental de la biología humana y son precursores de la síntesis de hormonas esteroideas y derivados eicosanoides. Los requerimientos de lípidos son satisfechos a través de la vía endógena que consiste en la formación de lípidos a nivel celular y la exógena la cual se da con la ingesta y absorción de grasas provenientes de la dieta. El conocimiento de estas vías es importante ya que es el punto de partida para un abordaje terapéutico adecuado y oportuno, pero a pesar de la facilidad de las metodologías de laboratorio para su cuantificación y diagnóstico, la hipercolesterolemia familiar sigue siendo subdiagnosticada. Discusión: para los clínicos es importante pues es una de las causas de eventos cardiovasculares prematuros. La presentación heterocigota tiene una prevalencia aproximada de 1/500 personas. En su mayoría son secundarias a la incapacidad en la actividad de los receptores LDL para el procesamiento del colesterol. Este compromiso de receptores está dado por múltiples mutaciones. Conclusión: las manifestaciones clínicas están relacionadas con niveles de LDL elevados (mayores de 190 mg/dL) y colesterol total mayor de 300 mg/dL presentes desde el nacimiento. Las estatinas son la primera línea de tratamiento, pero pueden resultar insuficientes requiriendo tratamientos adicionales con ezetimiba, secuestradores de ácidos biliares e inhibidores de la PCSK9.

Genetic testing in dyslipidaemia: An approach based on clinical experience

We have used DNA sequencing in our lipid clinic for >20 years. Dyslipidaemia is typically ascertained biochemically. For moderate deviations in the lipid profile, the etiology is often a combination of a polygenic susceptibility component plus secondary non-genetic factors. For severe dyslipidaemia, a monogenic etiology is more likely, although a discrete single-gene cause is frequently not found. A severe phenotype can also result from strong polygenic predisposition that is aggravated by secondary factors. A young age of onset plus a family history of dyslipidaemia or atherosclerotic cardiovascular disease can suggest a monogenic etiology. With severe dyslipidaemia, clinical examination focuses on detecting manifestations of monogenic syndromic conditions. For all patients with dyslipidaemia, secondary causes must be ruled out. Here we describe an experience-based practical approach to genetic testing of patients with severe deviations of low-density lipoprotein, triglycerides, high-density lipoprotein and also combined hyperlipidaemia and dysbetalipoproteinemia.