Effect of the LDL receptor mutation type on incident major adverse cardiovascular events in familial hypercholesterolaemia

Influence of Polygenic Background on the Clinical Presentation of Familial Hypercholesterolemia

BACKGROUND

Heterozygous familial hypercholesterolemia (FH) is among the most common genetic conditions worldwide that affects ≈ 1 in 300 individuals. FH is characterized by increased levels of low-density lipoprotein cholesterol (LDL-C) and increased risk of coronary artery disease (CAD), but there is a wide spectrum of severity within the FH population. This variability in expression is incompletely explained by known risk factors. We hypothesized that genome-wide genetic influences, as represented by polygenic risk scores (PRSs) for cardiometabolic traits, would influence the phenotypic severity of FH.

METHODS

We studied individuals with clinically diagnosed FH (n=1123) from the FH Canada National Registry, as well as individuals with genetically identified FH from the UK Biobank (n=723). For all individuals, we used genome-wide gene array data to calculate PRSs for CAD, LDL-C, lipoprotein(a), and other cardiometabolic traits. We compared the distribution of PRSs in individuals with clinically diagnosed FH, genetically diagnosed FH, and non-FH controls and examined the association of the PRSs with the risk of atherosclerotic cardiovascular disease.

RESULTS

Individuals with clinically diagnosed FH had higher levels of LDL-C, and the incidence of atherosclerotic cardiovascular disease was higher in individuals with clinically diagnosed compared with genetically identified FH. Individuals with clinically diagnosed FH displayed enrichment for higher PRSs for CAD, LDL-C, and lipoprotein(a) but not for other cardiometabolic risk factors. The CAD PRS was associated with a risk of atherosclerotic cardiovascular disease among individuals with an FH-causing genetic variant.

CONCLUSIONS

Genetic background, as expressed by genome-wide PRSs for CAD, LDL-C, and lipoprotein(a), influences the phenotypic severity of FH, expanding our understanding of the determinants that contribute to the variable expressivity of FH. A PRS for CAD may aid in risk prediction among individuals with FH.

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.

Increased FH-Risk-Score and Diabetes Are Cardiovascular Risk Equivalents in Heterozygous Familial Hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia (FH) is a genetic condition causing premature atherosclerotic cardiovascular disease (ASCVD). It is well established that patients with FH should be treated with statin therapy. However, there exists discordance concerning low-density lipoprotein cholesterol-lowering goals in the management of these patients between different guidelines worldwide. The objective was to compare the 10-year ASCVD risk of different subgroups of patients with and without FH including those with diabetes or a history of ASCVD and patients with FH within different FH-Risk-Score categories.

METHODS

This multinational observational study used data from 3 different prospective cohorts. A total of 3383 FH and 6917 non-FH controls matched for age and sex were included (104 363 person-years of follow-up). The 10-year incident ASCVD risk was assessed using Kaplan-Meier estimates, whereas the relative risk was estimated using Cox proportional hazards regression models.

RESULTS

FH patients with a high (score >20%) FH-Risk-Score (hazard ratio, 8.45 [95% CI, 6.69-10.67]; P<0.0001), FH patients with diabetes (hazard ratio, 7.67 [95% CI, 4.82-12.21]; P<0.0001), and non-FH patients with ASCVD (hazard ratio, 6.78 [95% CI, 5.45-8.42]; P<0.0001) had a significantly higher incident ASCVD risk over 10 years than the reference group (non-FH without ASCVD or diabetes). The observed 10-year risks in these groups were 32.1%, 30.8%, 30.0%, and 5.1%, respectively. The 10-year ASCVD risk associated with both FH and ASCVD was extremely high (observed risk of 50.7%; hazard ratio, 14.53 [95% CI, 12.14-17.38]; P<0.0001).

CONCLUSIONS

This study strongly suggests that the observed risk of FH patients with diabetes, history of ASCVD, and FH-Risk-Score >20% is as high or higher than non-FH individuals with a history of ASCVD. More aggressive management should be recommended for these patients.

Stratification in Heterozygous Familial Hypercholesterolemia: Imaging, Biomarkers, and Genetic Testing

PURPOSE OF REVIEW

Heterozygous familial hypercholesterolemia (HeFH) is the most common monogenic autosomal dominant disorder. However, the condition is often underdiagnosed and undertreated. The objective of this review is to provide an update on the risk stratification in patients with HeFH, incorporating new cardiovascular imaging techniques, various biomarkers, and genetic studies.

RECENT FINDINGS

The diagnosis of HeFH places patients in a high cardiovascular risk category due to the increased incidence of premature atherosclerotic cardiovascular disease. However, the level of risk varies significantly among different individuals with HeFH. Achieving an optimal stratification of cardiovascular risk is crucial for establishing appropriate and accurate treatment and management strategies. Different new tools such as risk scores have emerged in recent years, aiding physicians in assessing the risk stratification for HeFH using imaging, biomarkers, and genetics. This review emphasizes that not all patients with HeFH face the same cardiovascular risk. By utilizing different assessment tools, we can identify those who require more intensive monitoring, follow-up, and treatment.

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.

Impact of conducting a genetic study on the management of familial hypercholesterolemia

BACKGROUND

Clinically diagnosed familial hypercholesterolemia (FH) may require a genetic test (GT) to confirm diagnosis. GT availability/accessibility is resource-dependent and usually restricted to specialized clinics. While GT has a diagnostic value, it has not yet defined its impact on long-term management and prognosis of FH.

OBJECTIVE

The aim was to identify the clinical characteristics associated with the request for a GT in suspected heterozygous FH.

METHODS

Retrospective study including adult patients with clinically suspected to be FH. Positive GT (GT+) was defined as having a pathogenic/likely pathogenic variant. Patients were stratified based on whether they had a genetic study conducted, and among those with a genetic study, according to those who did or did not have a GT+.

RESULTS

From 4854 patients included, 3090 were performed a GT (GT+: 2113). Median follow-up: 6.2 years. A younger age, FH-related physical signs, premature coronary disease, higher low-density lipoprotein cholesterol (LDLc) and lower body mass index and triglycerides, associated higher odds of being conducted a genetic study. These patients had higher baseline LDLc (252 mg/dL vs. 211 mg/dL among clinically diagnosed patients) and experienced larger reductions over the follow-up (157.7 mg/dL vs. 113.5 mg/dL, respectively). A similar pattern was observed among patients with GT+ (vs. negative GT). LDLc target attainment was low but increased to 66-95% when a triple combination with statin/ezetimibe/proprotein convertase subtilisin kexin type 9-inhibitor was used. Cardiovascular events occurred in 3.2% and 3.1% of patients who conducted/not conducted a genetic study. Patients conducted a genetic analysis and those with GT+ tended to present the events earlier.

CONCLUSIONS

Genetic study, vs. having a clinical-only diagnosis, impacts the management of FH. Cardiovascular prognosis was similar in both groups, perhaps as a result of the more intensive management of patients with a genetic study.

Metabolic systems approaches update molecular insights of clinical phenotypes and cardiovascular risk in patients with homozygous familial hypercholesterolemia

BACKGROUND

Homozygous familial hypercholesterolemia (HoFH) is an orphan metabolic disease characterized by extremely elevated low-density lipoprotein cholesterol (LDL-C), xanthomas, aortic stenosis, and premature atherosclerotic cardiovascular disease (ASCVD). In addition to LDL-C, studies in experimental models and small clinical populations have suggested that other types of metabolic molecules might also be risk factors responsible for cardiovascular complications in HoFH, but definitive evidence from large-scale human studies is still lacking. Herein, we aimed to comprehensively characterize the metabolic features and risk factors of human HoFH by using metabolic systems strategies.

METHODS

Two independent multi-center cohorts with a total of 868 individuals were included in the cross-sectional study. First, comprehensive serum metabolome/lipidome-wide analyses were employed to identify the metabolomic patterns for differentiating HoFH patients (n = 184) from heterozygous FH (HeFH, n = 376) and non-FH (n = 100) subjects in the discovery cohort. Then, the metabolomic patterns were verified in the validation cohort with 48 HoFH patients, 110 HeFH patients, and 50 non-FH individuals. Subsequently, correlation/regression analyses were performed to investigate the associations of clinical/metabolic alterations with typical phenotypes of HoFH. In the prospective study, a total of 84 HoFH patients with available follow-up were enrolled from the discovery cohort. Targeted metabolomics, deep proteomics, and random forest approaches were performed to investigate the ASCVD-associated biomarkers in HoFH patients.

RESULTS

Beyond LDL-C, various bioactive metabolites in multiple pathways were discovered and validated for differentiating HoFH from HoFH and non-FH. Our results demonstrated that the inflammation and oxidative stress-related metabolites in the pathways of arachidonic acid and lipoprotein(a) metabolism were independently associated with the prevalence of corneal arcus, xanthomas, and supravalvular/valvular aortic stenosis in HoFH patients. Our results also identified a small marker panel consisting of high-density lipoprotein cholesterol, lipoprotein(a), apolipoprotein A1, and eight proinflammatory and proatherogenic metabolites in the pathways of arachidonic acid, phospholipid, carnitine, and sphingolipid metabolism that exhibited significant performances on predicting first ASCVD events in HoFH patients.

CONCLUSIONS

Our findings demonstrate that human HoFH is associated with a variety of metabolic abnormalities and is more complex than previously known. Furthermore, this study provides additional metabolic alterations that hold promise as residual risk factors in HoFH population.

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.