The complex molecular genetics of familial hypercholesterolaemia

What is the phenotype of heterozygous lipoprotein lipase deficiency?

PURPOSE OF REVIEW

Genetic testing of patients with severe hypertriglyceridemia often identifies a single heterozygous pathogenic variant in the LPL gene. The complex and variable phenotype associated with this genotype is the topic of this review.

RECENT FINDINGS

Previous research showed that heterozygosity for lipoprotein lipase deficiency is associated with reduced but variable post heparin lipolytic activity alongside inconsistent plasma lipid phenotypes ranging from normal to mild-to-moderate to severe hypertriglyceridemia. Recent research confirms and extends these observations, showing that a heterozygous individual can express a highly variable phenotype over time, depending on the presence of secondary factors. About 10% (range 8-20%) of patients with severe hypertriglyceridemia or multifactorial chylomicronemia syndrome are heterozygous for a rare pathogenic LPL variant, and a clinically relevant minority of these has recalcitrant or sustained hypertriglyceridemia.

SUMMARY

Heterozygosity for lipoprotein lipase deficiency predisposes to hypertriglyceridemia, which is sometimes severe depending on secondary factors, but is typically quite responsive to routine interventions such as diet, lifestyle and existing lipid-lowering therapies. However, many heterozygotes for pathogenic variants in LPL have completely normal plasma lipids.

Research Progress on Anti-Hyperlipidemia Peptides Derived from Foods

Hyperlipidemia is a metabolic disorder in which cholesterol (TC) and triglycerides (TGs) in the blood exceed the normal physiological levels. The incidence of the condition has continued to rise in recent years, posing a serious threat to public health. Its clinical treatment mainly relies on drug interventions, such as statins, fibrate, and niacin. Although these drugs have shown some efficacy in the treatment of hyperlipidemia, their adverse effects cannot be ignored. In contrast, naturally derived peptides have gradually become potential candidates for the prevention and treatment of hyperlipidemia due to their strong anti-hyperlipidemic activity and safety; examples of such peptides include those from dairy products, grains, legumes, and seafood. This review systematically summarizes peptides with anti-hyperlipidemic activity and analyzes their mechanisms of action, providing a theoretical basis for further research. In addition, we also outline some challenges facing the application of peptides, hoping to prevent hyperlipidemia and reduce its incidence by encouraging the consumption of foods rich in anti-hyperlipidemia peptides.

Chemical engineering of CRISPR-Cas systems for therapeutic application

Clustered regularly interspaced short palindromic repeats (CRISPR) technology has transformed molecular biology and the future of gene-targeted therapeutics. CRISPR systems comprise a CRISPR-associated (Cas) endonuclease and a guide RNA (gRNA) that can be programmed to guide sequence-specific binding, cleavage, or modification of complementary DNA or RNA. However, the application of CRISPR-based therapeutics is challenged by factors such as molecular size, prokaryotic or phage origins, and an essential gRNA cofactor requirement, which impact efficacy, delivery and safety. This Review focuses on chemical modification and engineering approaches for gRNAs to enhance or enable CRISPR-based therapeutics, emphasizing Cas9 and Cas12a as therapeutic paradigms. Issues that chemically modified gRNAs seek to address, including drug delivery, physiological stability, editing efficiency and off-target effects, as well as challenges that remain, are discussed.

Ezetimibe in the management of homozygous familial hypercholesterolaemia

BACKGROUND

Homozygous familial hypercholesterolaemia (HoFH) is a severe lipid disorder leading to accelerated atherosclerotic cardiovascular disease (ASCVD). This study aimed to evaluate the efficacy of ezetimibe, a cholesterol absorption inhibitor, in reducing low-density lipoprotein cholesterol (LDL-C) levels in patients with genetically confirmed HoFH.

METHODS

This retrospective review included 48 individuals with genetically confirmed HoFH attending the Lipid Clinic at an Academic Hospital in Johannesburg, South Africa. All patients were on stable high-intensity statin therapy for at least 6 months before starting ezetimibe 10 mg orally daily. Lipid profiles at baseline and after 3 and 6 months of ezetimibe therapy were documented. Responders (LDL-C reduction ≥20%) were compared to nonresponders (LDL-C reduction <20%).

RESULTS

Ezetimibe led to a 19.1% further reduction in LDL-C at 6 months. Among the participants, 23 were considered responders and 25 were nonresponders. Responders showed a 26.4% LDL-C reduction at 3 months and 31.6% at 6 months, compared to nonresponders with 8.5% and 5.9% reductions in LDL-C respectively. Individuals with the null LDL receptor variant c.1285G>A (p.Val429Met) were less likely to respond. However, response to ezetimibe was highly variable across all pathogenic variants.

CONCLUSION

Ezetimibe, in combination with high-intensity statin therapy, significantly reduces LDL-C levels in patients with genotypically confirmed HoFH. However, the response to ezetimibe is highly variable and unpredictable across genotypes. This study supports the inclusion of ezetimibe in the treatment regimen for all HoFH patients to reduce the risk of ASCVD. Further studies are needed to understand the variable responses to ezetimibe among different genotypes and in HoFH individuals with the same genotype.

Lerodalcibep and evolocumab for the treatment of homozygous familial hypercholesterolaemia with PCSK9 inhibition (LIBerate-HoFH): a phase 3, randomised, open-label, crossover, non-inferiority trial

BACKGROUND

Lerodalcibep, a small binding anti-PCSK9 protein (adnectin), showed effective LDL cholesterol reduction in heterozygous familial hypercholesterolaemia. We aimed to assess the safety and efficacy of lerodalcibep and evolocumab in a globally diverse homozygous familial hypercholesterolaemia population.

METHODS

This phase 3, randomised, open-label, crossover, non-inferiority study consisted of two 24-week treatment periods separated by an 8-week washout. The study was conducted in 12 lipid clinics in six countries (India, Israel, Norway, South Africa, Türkiye, and the USA). Patients aged 10 years or older with genetically confirmed homozygous familial hypercholesterolaemia were randomly assigned by computer-generated randomisation scheme performed centrally via interactive response technology to either monthly lerodalcibep 300 mg (1·2 mL subcutaneous injection) or monthly evolocumab 420 mg (subcutaneous 9 min infusion of 3·5 mL) for 24 weeks (period A) followed by an 8-week washout and then crossed over to the alternate therapy for the next 24 weeks (period B). The trial was open label, but all efficacy parameters were masked to patients, study staff, and the sponsor from randomisation. The primary efficacy endpoint was the percent change from baseline (day 1 of period A) in LDL cholesterol concentration to week 24 for period A and B. The intention-to-treat (ITT) population, defined as all randomly assigned patients, was used for the primary analysis. The safety population included all patients who received any study medication. The margin used to establish non-inferiority was 6%. The trial is registered with ClinicalTrials.gov (NCT04034485) and EudraCT (2019-003611-62), and has now finished.

FINDINGS

Patients were enrolled from Nov 11, 2019, to July 2, 2021, and the final study visit took place on Aug 8, 2022. Of 82 patients screened, 66 entered period A (ITT population). The mean age was 28·7 years (SD 15·2); 20 (30%) of 66 were paediatric patients; 36 (55%) of 66 were female and 30 (45%) of 66 were male; and the mean baseline LDL cholesterol was 10·59 mmol/L (SD 4·37). Mean LDL cholesterol reduction by ITT analysis at week 24 was -4·9% (SE 3·5) on lerodalcibep compared with -10·3% (3·5) on evolocumab; the mean difference between treatments was 5·4% (95% CI -0·2 to 11·1), which did not show non-inferiority at the prespecified 6% margin. LDL cholesterol response varied considerably across the patient population but was generally similar in the same patients with both lerodalcibep and evolocumab. When averaged across all monthly visits, LDL cholesterol response was -9·1% (SE 3·2) on lerodalcibep and -10·8% (3·2) on evolocumab. Importantly, genotyping and free PCSK9 suppression were not predictive of response. Both drugs were well tolerated, with no treatment-related serious adverse events. Injection site reactions were reported in one (2%) of 65 patients on lerodalcibep and 15 (24%) of 62 patients on evolocumab.

INTERPRETATION

The LDL cholesterol response was highly variable, but generally similar in patients treated with both lerodalcibep and evolocumab. Importantly, the study showed the inability to predict response based on genotyping, reinforcing the rationale for PCSK9 inhibition in all patients with homozygous familial hypercholesterolemia and continuing its use in responders.

FUNDING

LIB Therapeutics.

Investigation of the genetic background of familial hypercholesterolemia in a Turkish cohort and its clinical implications

OBJECTIVE

Familial hypercholesterolemia (FH) is a genetic disorder characterized by elevated plasma cholesterol and an increased risk of early-onset coronary artery disease (CAD). FH has a complex genetic basis. Advances in molecular genetic techniques have deepened our understanding of FH, which is critical for accurate classification, CAD risk assessment, and optimized treatment strategies. This study aimed to evaluate the monogenic etiologies of FH and polygenic background as a possible cause of clinical FH phenotype and their relationship to clinical outcomes in a Turkish cohort.

METHODS

Patients were selected based on the Simon Broome Criteria. Various molecular techniques were employed, including Sanger sequencing, multiplex-ligation dependent probe amplification (MLPA), next-generation sequencing (NGS) panel analysis, and RNA-based studies. For the first time in a Turkish FH cohort, we calculated 6-single nucleotide polymorphism (SNP) and 12-SNP scores and compared them with a control group.

RESULTS

Multiple variants were identified, including 2 novel variants and a synonymous splice region variant in LDLR, which was shown to disrupt splicing through RNA analysis. The 6-SNP and 12-SNP scores displayed patterns consistent with other populations.

CONCLUSION

Our findings suggest subtle differences in the monogenic etiology of FH in the Turkish population, with variant negative patients predominantly exhibiting polygenic background. Additionally, polygenic factors appear to influence the phenotype even in variant-positive individuals.

Performance of LDL-C only compared to the Dutch Lipid Clinic Network Score for screening of familial hypercholesterolaemia: the Austrian experience and literature review

AIMS

Familial hypercholesterolaemia (FH) is a severely underdiagnosed, inherited disease, causing dyslipidaemia and premature atherosclerotic cardiovascular disease. In order to facilitate screening in a broad clinical spectrum, we aimed to analyse the current yield of routine genetic diagnostics for FH and to evaluate the performance of the Dutch Lipid Clinic Network Score (DLCNS) compared to a single value, the off-treatment LDL-cholesterol exceeding 190 mg/dL.

METHODS AND RESULTS

We investigated all patients that underwent molecular genotyping routinely performed for FH over a 4-year period in two Austrian specialist lipid clinics. Variants reported in FH-causing genes including LDLR, APOB, PCSK9, LDLRAP, and APOE were collected and classified. For clinical classification, the DLCNS was calculated retrospectively and compared to the original scores documented in patient charts. Additionally, a literature review on comparisons of DLCNS to LDL-C was performed. Of 469 patients tested, 21.3% had a disease-causing variant. A median of 3 out of 8 (excluding genotyping results and LDL-C) DLCNS criteria were unavailable. DLCNS was documented in 48% of cases, with significant discrepancies compared to retrospective scoring (P < 0.001). DLCNS did not outperform off-treatment LDL-C alone (Δ = 0.006; P = 0.660), analogously to several reports identified in the literature. A single cut-off of 190 mg/dL LDL-C compared to DLCNS ≥ 6 showed excellent sensitivity (84.9% vs. 53.8%) and acceptable specificity (39.0% vs. 84.1%).

CONCLUSION

Missing criteria and severe discrepancies observed between retrospective and on-site scoring by treating physicians were highly prevalent, confirming limited utility of DLCNS in clinical routine and warranting a single off-treatment LDL-C cut-off of 190 mg/dL for enhanced index-case identification.

Large-Scale Functional Characterization of Low-Density Lipoprotein Receptor Gene Variants Improves Risk Assessment in Cardiovascular Disease

Limited access to functional information of genetic variants reduces the applicability of genetic tools for precision medicine applications in cardiovascular disease. We established an automated analysis platform based on multiplexed high-content imaging and derived in-depth functional data for several hundred LDLR gene variants. Residual low-density lipoprotein receptor activity of genetic variants impacted the risk for cardiovascular disease and elevated low-density lipoprotein cholesterol as well as the utilization of lipid-lowering and combination therapy. This enables increased risk stratification for carriers of LDLR gene variants and opens up new opportunities for improved diagnosis, risk assessment, and treatment selection in familial hypercholesterolemia.

Familial hypercholesterolemia in Chinese children and adolescents: a multicenter study

BACKGROUND

Familial hypercholesterolemia (FH) is an inherited disorder mainly marked by increased low-density lipoprotein cholesterol (LDL-C) concentrations and a heightened risk of early-onset arteriosclerotic cardiovascular disease (ASCVD). This study seeks to characterize the genetic spectrum and genotype‒phenotype correlations of FH in Chinese pediatric individuals.

METHODS

Data were gathered from individuals diagnosed with FH either clinically or genetically at multiple hospitals across mainland China from January 2016 to June 2024.

RESULTS

In total, 140 children and adolescents (mean age of 6.00 years) with clinically and genetically diagnosed FH were enrolled in the study, with 87 distinct variants identified in the LDLR, APOB and PCSK9 genes. Among the variants, 11 variants were newly identified worldwide, with 9 classified as "pathogenic" or "likely pathogenic", and 2 classified as "variants of uncertain significance". Additionally, the 5 most common variants in the study were c.1448G > A (p.W483*), c.1879G > A (p.A627T), c.1216C > A (p.R406R), and c.1747C > T (p.H583Y) in the LDLR gene, as well as c.10579C > T (p.R3527W) in the APOB gene, accounting for 49.29% (69/140) of all patients. These variants are primarily observed in the Asian or Chinese population and are distinct from those present in Caucasian groups. In this cohort, 105 patients were diagnosed with heterozygous FH (HeFH), while 35 were diagnosed with homozygous FH (HoFH). Finally, only 28.57% of the patients (40/140) were using lipid-lowering medications with 33.33% of HoFH patients initiating treatment after the age of 8. Additionally, only 3 compound heterozygous patients (2.14%) underwent liver transplantation because of significantly high lipid levels.

CONCLUSION

This study reveals the variable genotypes and phenotypes of children with FH in China and illustrates that the genotypes in the Chinese population differ from those in Caucasians, providing a valuable dataset for the clinical genetic screening of FH in China. Furthermore, the older age at diagnosis and treatment highlights the underdiagnosis and undertreatment of Chinese FH pediatric patients, suggesting that early identification should be improved through lipid or genetic screening, and that more timely and regular pharmacological treatments should be implemented.

SYNTAX I score is associated with genetically confirmed familial hypercholesterolemia in chinese patients with coronary heart disease

BACKGROUND

Familial hypercholesterolemia (FH) is a genetically inherited disorder caused by monogenic mutations or polygenic deleterious variants. Patients with FH innate with significantly elevated risks for coronary heart disease (CHD). FH prevalence based on genetic testing in Chinese CHD patients is missing. Whether classical index of coronary atherosclerosis severity can be used as indicators of FH needs to be explored. To investigate the FH prevalence in Chinese CHD patients and the association of SYNTAX I score with FH genotype.

METHODS

The monogenic and polygenic FH related genes were genotyped in 400 consecutively enrolled CHD patients. The clinical characteristics and SYNTAX I scores were analyzed in a retrospective nested case-control study.

RESULTS

The prevalence of genetically confirmed FH in our CHD cohort was 8.75%. The cLDL-C level, SYNTAX I scores and incidences of triple vessel lesions in FH patients were significantly higher, while cLDL-C and SYNTAX I scores were independent risk factors for FH. Furthermore, cLDL-C levels of polygenic FH were significantly lower than monogenic FH, while their severity of coronary atherosclerosis was comparable.

CONCLUSIONS

Our study revealed that the SYNTAX I score was an independent risk factor for FH. Besides, polygenic origin of FH should be taken into consideration for CHD patients suspected of FH.

Clinical and biochemical features of atherogenic hyperlipidemias with different genetic basis: A comprehensive comparative study

Patients with genetically-based hyperlipidemias exhibit a wide phenotypic variability. Investigation of clinical and biochemical features is important for identifying genetically-based hyperlipidemias, determining disease prognosis, and initiating timely treatment. We analyzed genetic data from 3374 samples and compared clinical data, lipid levels (low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol, triglycerides, and lipoprotein (a)), frequency, age at onset of coronary heart disease (CHD), and the severity of carotid and femoral atherosclerosis (plaque number, maximum stenosis, total stenosis, maximum plaque height, and plaque score) among patients with familial hypercholesterolemia (FH), familial dysbetalipoproteinemia (FD), polygenic hypercholesterolemia (HCL), severe HCL, and those without lipid disorders (n = 324). FH patients exhibited the highest LDL-C (median 8.03 mmol/L, p < 0.001). FD patients had elevated triglyceride levels (median 4.10 mmol/L), lower LDL-C (median 3.57 mmol/L), and high-density lipoprotein cholesterol (median 1.03 mmol/L) compared to FH, polygenic HCL, and severe HCL, p < 0.05. FH and FD patients had similar early onset of CHD, with a median age of 44 and 40 years and comparable frequencies of 29.5% and 31.0%, respectively. They were more likely to develop CHD than subjects without lipid disorders (p = 0.042 and p < 0.001, respectively). Additionally, FH patients had higher a carotid plaque number, total carotid stenosis, and carotid plaque score. This study presents the first simultaneous comparison of clinical and biochemical features among FD, FH, polygenic, and severe HCL, along with the first comprehensive evaluation of carotid and femoral atherosclerosis ultrasound parameters in FD patients. The results highlight distinct phenotypic features unique to each hyperlipidemia analyzed and underscore FH and FD as the most atherogenic hyperlipidemias.

Targeted NGS Revealed Pathogenic Mutation in a 13-Year-Old Patient with Homozygous Familial Hypercholesterolemia: A Case Report

Familial hypercholesterolemia is an autosomal hereditary disease defined by an increased level of low-density lipoprotein cholesterol (LDL-C), which predisposes significant risks for premature cardiovascular disorders. We present a family trio study: proband, a 13-year-old Kazakh girl with homozygous familial hypercholesterolemia (HoFH) and her parents. HoFH is much more rare and severe than a heterozygous form of the disorder. HoFH patients generally present with LDL-C levels exceeding 13 mmol/L, resulting in early and life-threatening cardiovascular events within the first decades of life. In cases of neglected treatment, young patients have a risk of death from coronary diseases before the age of 30. The aim of this research was to identify genetic mutations in the affected patient and her parents. Genetic testing was necessary due to highly elevated LDL-C levels and the presence of multiple xanthomas. Targeted next-generation sequencing (NGS) was performed in this study using the Illumina TruSight cardio panel, which targets 174 genes related to cardiac disorders. The girl was diagnosed with HoFH based on the results of genetic testing. A biallelic mutation was observed in exon 3 of the low-density lipoprotein receptor (LDLR): c. 295 G>A (p.Glu99Lys). Sanger sequencing confirmed that the mutant gene was inherited from both parents. After confirming the genetic diagnosis of HoFH, the patient was treated with LDL apheresis and statins. This case report is the first study of HoFH in a pediatric patient from the Central Asian region. Globally, it emphasizes the need for increased clinical awareness among healthcare providers, as early detection and intervention are important for improving outcomes, particularly in pediatric patients with this rare genetic disorder.

Pathogenicity of the LDLR c.97C>T (p.Gln33Ter) Mutation in Familial Hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia (FH) is a hereditary disease caused mainly by mutations in the gene encoding the low-density lipoprotein receptor (LDLR). This study aimed to confirm the pathogenicity of the LDLR c.97C>T (p.Gln33Ter) mutation through in vitro functional validation and determine whether this nonsense mutation induces nonsense-mediated mRNA decay (NMD).

METHODS

The proband and his family were included in accordance with Chinese Expert Consensus on FH screening. The disease-causing mutations were fund using whole-exome sequencing and were confirmed using bidirectional Sanger sequencing. The pathogenicity of the mutation was predicted using in silico analysis. The LDLR c.97C>T (p.Gln33Ter) mutation was generated using site-directed mutagenesis and expressed in HEK293T cells lacking endogenous LDLR expression. The effects of this alteration on LDLR expression and LDL uptake were assessed using flow cytometry, quantitative polymerase chain analysis, western blotting, and confocal laser scanning microscopy.

RESULTS

The mutation that causes FH in this family was LDLR c.97C>T (p.Gln33Ter), and family members with this mutation exhibited elevated levels of low-density lipoprotein cholesterol (LDL-C). The cell experiment results showed that this mutation prevented the synthesis of LDLR protein and caused the cells to lose their LDL uptake ability.

CONCLUSION

LDLR c.97C>T (p.Gln33Ter) is a pathogenic FH mutation. However, this nonsense mutation did not induce NMD.

Cardiovascular disease risk in patients with elevated LDL-C levels: FH vs. non-FH

Introduction

Coronary artery disease (CAD) remains the primary cause of death worldwide, and familial hypercholesterolemia (FH) is a common disease that leads to CAD. This study aimed to explore the difference in CAD risk between FH and non-FH patients with high low-density lipoprotein cholesterol (LDL-C) levels.

Methods

Individuals (≥18 years) who underwent coronary angiography (CAG) from June 2016 to September 2020 were consecutively enrolled. Participants with LDL-C levels ≥4.0 mmol/L were ultimately included in this study. For all participants, next-generation sequencing was performed with expanded gene panels including 11 genes (LDLR, APOB, PCSK9, LDLRAP1, ABCG5, ABCG8, LIPA, LPA, APOBR, LRPAP1, and STAP1).

Results

A total of 223 individuals were included in this study. According to the CAG findings, 199 CAD patients and 24 non-CAD patients were included. The proportions of FH genes, regardless of whether 3 major genes or all 11 genes were sequenced, were not significantly different between the CAD and non-CAD groups (P > 0.05). In addition, all CAD patients were divided into a triple vessel disease (TVD) group and a non-TVD group. The TVD group had a greater proportion of patients with mutations in 3 FH major genes (P < 0.05). In addition, TC, LDL-C and modified LDL-C (MLDL-C) levels were higher and the estimated glomerular filtration rate (eGFR) was lower in the TVD group than in the non-TVD group (all P < 0.05). However, multivariate logistic regression analyses revealed that only the eGFR was an independent risk factor for TVD (OR 0.99; 95% CI: 0.98-1.00, P < 0.05). To eliminate the impact of the eGFR, subgroup analysis was conducted, and the results indicated that among CAD patients in the high-eGFR group, having FH mutations in 3 major genes was an independent risk factor for TVD (OR 3.00; 95% CI: 1.16-7.79, P < 0.05). In total, 104 FH-related mutations were detected in this study.

Conclusions

FH mutation did not increase the rate of CAD in individuals with an MLDL-C level ≥4.0 mmol/L. However, among CAD patients (MLDL-C level ≥4.0 mmol/L) with almost normal renal function (≥87.4 ml/min/1.73 m2), the probability of enduring TVD in those with FH mutations in 3 major genes was 3.00 times greater than that in those without FH mutations.

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.

Lipidomic profiling in patients with familial hypercholesterolemia: Abnormalities in glycerolipids and oxysterols

OBJECTIVES AND AIM

This study aimed to identify precise biomarkers and develop targeted therapeutic strategies for preventing premature atherosclerotic cardiovascular disease in patients with familial hypercholesterolemia (FH) by investigating the quantitative and qualitative abnormalities in the metabolic network of lipids in these patients using an advanced lipidomics platform.

DESIGN & METHODS

The study population comprised 18 homozygous (HoFH), 18 heterozygous (HeFH) FH patients, and 20 healthy controls. Cholesterol oxidation products (oxysterol, COPs) and main lipid classes were determined using gas chromatography-mass spectrometry. Results were expressed as percentages of total fat matter for lipid classes and percentages of total COPs for oxysterols. The principal component analysis (PCA) was also carried out, to highlight the correlation between studied parameters and groups investigated.

RESULTS

Patients (both HoFH and HeFH) showed lower content of free fatty acids (FFAs) and greater values of triacylglycerols (TAGs) in comparison to controls. HoFH showed lower monoacylglycerols (P<0.01) and higher free cholesterol (FC) (P<0.05) when compared to HeFH and controls. The total content of COPs ranged from 1.96 to 4.25 mg/dL, from 2.27 to 4.05 mg/dL, and from 0.79 to 4.12 mg/dL in healthy controls, HoFH and HeFH groups, respectively, with no significant differences between patients and controls. In general, the 7α-hydroxycholesterol (7α-HC) was greater than other COPs. However, no significant differences were found between the three studied groups. Moreover, an opposite trend was observed between 7α-HC and 7-ketocholesterol (7-KC). Additionally, when PCA was carried out, the first two PCs explained 92.13 % of the total variance, of which the PC1 describes 53.94 % of variance mainly correlated to TAGs, diacylglycerols (DAGs), and 7-KC. On the other hand, the PC2 was correlated primarily for FFAs, FC and esterified sterols (E-STE).

CONCLUSIONS

In conclusion, abnormal levels of TAGs, DAGs and 7-KC were associated with HeFH while HoFH was associated with the abnormal amount of E-STE.

The Importance of Genetic Testing for Familial Hypercholesterolemia: A Pediatric Pilot Study

Background and Objectives: Familial hypercholesterolemia (FH) is a genetic disease that is massively underdiagnosed worldwide. Affected patients are at high risk of cardiovascular events at young ages. Early intervention in childhood could help prevent heart attacks and cerebral strokes in these patients. Materials and Methods: We conducted an interventional study including 10 patients that previously underwent genetic testing for familial hypercholesterolemia. These patients received lifestyle and diet recommendations that they followed for a year before being reevaluated. Results: Patients with negative genetic testing were able to achieve lower levels in their lipid panel values compared to the patients with positive genetic testing, with lifestyle changes alone. LDL-cholesterol levels decreased by 18.5% in patients without FH while patients genetically confirmed with FH failed to achieve lower LDL-cholesterol levels without medication. Conclusions: Genetic testing for FH is not always part of screening algorithms for FH. Some studies even advise against it. Our study proved the importance of genetic testing for FH when suspecting this disorder and choosing the treatment course for patients.

Advances in nucleic acid-targeted therapies for cardiovascular disease prevention

Nucleic acid-based therapies are being rapidly developed for prevention and management of cardiovascular diseases (CVD). Remarkable advancements have been achieved in the delivery, safety, and effectiveness of these therapeutics in the past decade. These therapies can also modulate therapeutic targets that cannot be sufficiently addressed using traditional drugs or antibodies. Among the nucleic acid-targeted therapeutics under development for CVD prevention are RNA-targeted approaches, including antisense oligonucleotides (ASO), small interfering RNAs (siRNA), and novel genome editing techniques. Genetic studies have identified potential therapeutic targets that are suggested to play a causative role in development and progression of CVD. RNA- and DNA-targeted therapeutics can be particularly well delivered to the liver, where atherogenic lipoproteins and angiotensinogen (AGT) are produced. Current targets in lipid metabolism include proprotein convertase subtilisin/kexin type 9 (PCSK9), apolipoprotein A (ApoA), apolipoprotein C3 (ApoC3), angiopoietin-like 3 (ANGPTL3). Several large-scale clinical development programs for nucleic acid-targeted therapies in cardiovascular prevention are under way, which may also be attractive from a therapy adherence point of view, given the long action of these therapeutics. In addition to genome editing, the concept of gene transfer is presently under assessment in preclinical and clinical investigations as a potential approach for addressing low-density lipoprotein receptor deficiency. Furthermore, ongoing research is exploring the use of RNA-targeted therapies to treat arterial hypertension by reducing hepatic angiotensinogen (AGT) production. This review summarizes the rapid translation of siRNA and ASO therapeutics as well as gene editing into clinical studies to treat dyslipidemia and arterial hypertension for CVD prevention. It also outlines potential innovative therapeutic options that are likely relevant to the future of cardiovascular medicine.

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.

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.

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.

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.