Diagnosing heterozygous familial hypercholesterolemia using new practical criteria validated by molecular genetics

Assessment of physicians' awareness and knowledge of familial hypercholesterolemia in Saudi Arabia: Is there a gap?

Background

The scarcity of familial hypercholesterolemia (FH) cases reported in Saudi Arabia might be indicative of a lack of awareness of this common genetic disease among physicians.

Objective

To assess physicians’ awareness, practice, and knowledge of FH in Saudi Arabia.

Methods

This is a cross-sectional study conducted among physicians at four tertiary hospitals in Riyadh, Saudi Arabia between March 2016 and May 2016 using a self-administered questionnaire.

Results

A total of 294 physicians completed the survey (response rate 90.1%). Overall, 92.9% of the participants have poor knowledge of FH while only 7.1% have acceptable knowledge. The majority (68.7%) of physicians rated their familiarity with FH as average or above average, and these had higher mean knowledge scores than participants with self-reported below average familiarity (mean 3.4 versus 2.6) (P < 0.001). Consultant physicians were 4.2 times more likely to be familiar with FH than residents or registrars (OR = 4.2, 95% CI = 1.9–9.1, P < 0.001). Physicians who currently managed FH patients had higher mean knowledge scores compared to those without FH patients in their care (3.5 versus 2.9) (P = 0.006). In addition, there were statistically significant differences between physicians’ mean knowledge scores and their ages, levels of training, and years in practice. Moreover, a substantial deficit was identified in the awareness of various clinical algorithms to diagnose patients with FH, cascade screening, specialist lipid services, and the existence of statin alternatives, such as proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors.

Conclusion

A substantial deficit was found in the awareness, knowledge, practice, and detection of FH among physicians in Saudi Arabia. Extensive educational programs are required to raise physician awareness and implement best practices; only then can the impact of these interventions on FH management and patient outcome be assessed.

Lipoprotein apheresis in the treatment of dyslipidaemia - the Czech Republic experience

In 1984, we started using therapeutic plasmapheresis (plasma exchange) as a method of extracorporeal lipoprotein elimination for the treatment of hypercholesterolemic patients. We evaluated the results of long-term therapy in 14 patients, 8 men and 6 women. The average age was 55.6+/-13.2 (range 28-70), median 59.5 years. 14 patients were diagnosed with familial hypercholesterolemia (FH): 5 homozygous, 9 heterozygous. Ten patients in the group were treated using immunoadsorption lipoprotein apheresis and 4 using hemorheopheresis. Immunoapheretic interventions decreased LDL-cholesterol (82+/-1 %), ApoB (73+/-13 %) and even Lp(a) by 82+/-19 %, respectively. Selected non-invasive methods are important for long-term and repeated follow-up. Carotid intima-media thickness showed improvement or stagnation in 75 % of the patients. Biomarkers of endothelial dysfunction such as endoglin (in the control group: 3.85+/-1.25 microg/l, in lipoprotein apheresis-treated hypercholesterolemic individuals 5.74+/-1.47 microg/l), CD40 ligand (before lipoprotein apheresis: 6498+/-2529 ng/l, after lipoprotein apheresis: 4057+/-2560 ng/l) and neopterin (before lipoprotein apheresis: 5.7+/-1.1 nmol/l, after lipoprotein apheresis: 5.5+/-1.3 nmol/l) related to the course of atherosclerosis, but did not reflect the actual activity of the disease nor facilitate the prediction or planning of therapy. Hemorheopheresis may improve blood flow in microcirculation in familial hypercholesterolemia and also in some other microcirculation disorders via significantly decreased activity of thrombomodulin (p<0.0001), tissue factor (p<0.0001), aggregation of thrombocytes (p<0.0001) and plasma and whole blood viscosity (p<0.0001). In conclusion, lipoprotein apheresis and hemorheopheresis substantially lowered LDL-cholesterol in severe hypercholesterolemia. Our experience with long-term therapy also shows good tolerance and a small number of complications (6.26 % non-serious clinical complications).

Beyond cascade screening: detection of familial hypercholesterolaemia at childhood immunization and other strategies

PURPOSE OF REVIEW

Familial hypercholesterolaemia is a common genetic disorder that accelerates premature coronary heart disease. Although effective treatments are available, the majority of individuals remain undiagnosed. We review new evidence for improving the detection of familial hypercholesterolaemia.

RECENT FINDINGS

Recent studies have demonstrated that universal screening of children for familial hypercholesterolaemia may be highly effective at the time of immunization if combined with reverse cascade testing of adult family members, who have a more immediate risk of a coronary event. Alerts on laboratory reports and the application of bioinformatics to electronic health records may also be useful for identifying familial hypercholesterolaemia in community settings. Effective detection, diagnosis, and codification of familial hypercholesterolaemia are essential for the development of registries.

SUMMARY

Although the cost-effectiveness of screening programs for familial hypercholesterolaemia in childhood remains to be established, combining universal and reverse cascade screening, complemented by opportunistic identification of individuals in high-risk settings, use of laboratory alerts, and screening of electronic health records are likely to have a high yield in the detection of familial hypercholesterolaemia in the community.

Family-specific aggregation of lipid GWAS variants confers the susceptibility to familial hypercholesterolemia in a large Austrian family

BACKGROUND AND AIMS

Hypercholesterolemia confers susceptibility to cardiovascular disease (CVD). Both serum total cholesterol (TC) and LDL-cholesterol (LDL-C) exhibit a strong genetic component (heritability estimates 0.41-0.50). However, a large part of this heritability cannot be explained by the variants identified in recent extensive genome-wide association studies (GWAS) on lipids. Our aim was to find genetic causes leading to high LDL-C levels and ultimately CVD in a large Austrian family presenting with what appears to be autosomal dominant inheritance for familial hypercholesterolemia (FH).

METHODS

We utilized linkage analysis followed by whole-exome sequencing and genetic risk score analysis using an Austrian multi-generational family with various dyslipidemias, including elevated TC and LDL-C, and one family branch with elevated lipoprotein (a) (Lp(a)).

RESULTS

We did not find evidence for genome-wide significant linkage for LDL-C or apparent causative variants in the known FH genes rather, we discovered a particular family-specific combination of nine GWAS LDL-C SNPs (p = 0.02 by permutation), and putative less severe familial hypercholesterolemia mutations in the LDLR and APOB genes in a subset of the affected family members. Separately, high Lp(a) levels observed in one branch of the family were explained primarily by the LPA locus, including short (<23) Kringle IV repeats and rs3798220.

CONCLUSIONS

Taken together, some forms of FH may be explained by family-specific combinations of LDL-C GWAS SNPs.

An insight into familial hypercholesterolemia in Greece: rationale and design of the Hellenic Familial Hypercholesterolemia Registry (HELLAS-FH)

Familial hypercholesterolemia (FH) is the most common metabolic genetic disorder. It is estimated that around 13 million people worldwide have FH. At the same time, only 25% of FH patients have been diagnosed. Moreover, these patients are often undertreated. The true prevalence of FH in Greece is unknown, but it is estimated that there are at least 40,000 FH patients nationwide pointing to a prevalence of 1:250. Patients with FH are at a high risk for cardiovascular events and death at an early age. Therefore, prompt detection of these patients is of pivotal importance in order to implement appropriate preventive measures at a young age. Patient registries are a powerful tool for recording and monitoring a disease and promoting clinical practices, thus contributing to improved outcomes and reduction of healthcare costs. National registries of FH patients have been a success in the Netherlands, Spain and Wales. As Greece did not have a national FH registry, the Hellenic Atherosclerosis Society has organized, established and funded the Hellenic Familial Hypercholesterolemia (HELLAS-FH) national registry in order to promote a better understanding of FH in our country.

Prevention of cardiovascular disease in patients with familial hypercholesterolaemia: The role of PCSK9 inhibitors

Familial hypercholesterolaemia is an autosomal dominant inherited disorder characterised by elevated low-density lipoprotein cholesterol levels and consequently an increased risk of atherosclerotic cardiovascular disease (ASCVD). Familial hypercholesterolaemia is relatively common, but is often underdiagnosed and undertreated. Cardiologists are likely to encounter many individuals with familial hypercholesterolaemia; however, patients presenting with premature ASCVD are rarely screened for familial hypercholesterolaemia and fasting lipid levels are infrequently documented. Given that individuals with familial hypercholesterolaemia and ASCVD are at a particularly high risk of subsequent cardiac events, this is a missed opportunity for preventive therapy. Furthermore, because there is a 50% chance that first-degree relatives of individuals with familial hypercholesterolaemia will also be affected by the disorder, the underdiagnosis of familial hypercholesterolaemia among patients with ASCVD is a barrier to cascade screening and the prevention of ASCVD in affected relatives. Targeted screening of patients with ASCVD is an effective strategy to identify new familial hypercholesterolaemia index cases. Statins are the standard treatment for individuals with familial hypercholesterolaemia; however, low-density lipoprotein cholesterol targets are not achieved in a large proportion of patients despite treatment. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have been shown to reduce low-density lipoprotein cholesterol levels considerably in individuals with familial hypercholesterolaemia who are concurrently receiving the maximal tolerated statin dose. The clinical benefit of PCSK9 inhibitors must, however, also be considered in terms of their cost-effectiveness. Increased awareness of familial hypercholesterolaemia is required among healthcare professionals, particularly cardiologists and primary care physicians, in order to start early preventive measures and to reduce the mortality and morbidity associated with familial hypercholesterolaemia and ASCVD.

Analysis of circulating miRNAs in patients with familial hypercholesterolaemia treated by LDL/Lp(a) apheresis

BACKGROUND

LDL/Lp(a) apheresis therapy is a well-established method of aggressively lowering LDL and Lp(a). Recently, miRNAs have been discussed as markers of vascular status including atherosclerosis. MiRNAs inhibit post-transcriptional processes through RNA duplex formation resulting in gene silencing or regulation of gene expression.

MATERIALS AND METHODS

We measured a profile of 175 plasma-circulating miRNAs using pre-defined Serum/Plasma Focus Human microRNA PCR Panels in pooled samples of 11 subjects with familial hypercholesterolaemia under long-term apheresis treatment. Subsequently we analysed expressions of ten pre-selected miRNAs potentially involved in lipid homeostasis in the same group of subjects. We compared plasma-circulating miRNA levels isolated from peripheral blood collected immediately before and after apheresis.

RESULTS

The greatest differences in plasma levels were found in miR-451a, miR-16, miR-19a/b, miR-223 and miR-185. In subsequent individual miRNA assay we detected a significant increase in miR-33b levels after apheresis (P < 0.05). Additionally, correlations between plasma lipids and miR-33a (P < 0.04) and miR-122 (P < 0.01) have been determined. Moreover, miR-122 levels in LDLR homozygotes were higher compared to heterozygotes after, but not before, apheresis treatment (P < 0.04).

CONCLUSIONS

LDL/Lp(a) apheresis has an impact on miRNAs associated with lipid homeostasis and vascular status.

Efficacy and safety of proprotein convertase subtilisin/kexin type 9 monoclonal antibody in adults with familial hypercholesterolemia

Proprotein convertase-subtilisin/kexin type 9 (PCSK9) monoclonal antibody is a new therapy to reduce low-density lipoprotein cholesterol (LDL-C) level in patients with familial hypercholesterolemia (FH). This pooled analysis aimed to estimate the efficacy and safety of PCSK9 antibody therapy in FH. Reports of randomized controlled trials (RCTs) comparing PCSK9 antibody to placebo were retrieved by a search of MEDLINE via PubMed, EMBASE, the Cochrane Library databases, ClinicalTrials.gov and Clinical Trial Results (up to November 30, 2015) with no language restriction. Data were abstracted by a standardized protocol. We found eight RCTs (1,879 patients with FH) for the pooled analysis. As compared with placebo, PCSK9 antibody therapy remarkably reduced LDL-C level (mean reduction: -48.54 %, 95 % CI: -53.19 to -43.88), total cholesterol (mean reduction: -31.08%, 95 % CI: -35.20 to -26.95), lipoprotein (a) (mean reduction: -20.44%, 95 % CI: -25.21 to -15.66), and apolipoprotein B (mean reduction: -36.32%, 95 % CI: -40.75 to -31.90) and elevated the level of high-density lipoprotein cholesterol (mean change: 6.29 %, 95 % CI: 5.12 to 7.46) and apolipoprotein A1(mean change: 4.86%, 95 % CI: 3.77 to 5.95). Therapy with and without PCSK9 antibodies did not differ in rate of adverse events (pooled rate: 50.86 % vs. 48.63%; RR: 1.03; 95 % CI: 0.92 to 1.15; P = 0.64; heterogeneity P = 0.13; I2= 40%) or serious adverse events (pooled rate: 7.14% vs. 6.74%; RR: 1.05; 95 % CI: 0.70 to 1.58; P = 0.80; heterogeneity P = 0.69; I2= 0%). PCSK9 antibody may be an effective and safe treatment for FH.

Analysis of Children and Adolescents with Familial Hypercholesterolemia

OBJECTIVE

To evaluate the effectiveness of criteria based on child-parent assessment in predicting familial hypercholesterolemia (FH)-causative mutations in unselected children with hypercholesterolemia.

STUDY DESIGN

LDLR, APOB, and PCSK9 genes were sequenced in 78 children and adolescents (mean age 8.4 ± 3.7 years) with clinically diagnosed FH. The presence of polygenic hypercholesterolemia was further evaluated by genotyping 6 low-density lipoprotein cholesterol (LDL-C)-raising single-nucleotide polymorphisms.

RESULTS

Thirty-nine children (50.0%) were found to carry LDLR mutant alleles but none with APOB or PCSK9 mutant alleles. Overall, 27 different LDLR mutations were identified, and 2 were novel. Children carrying mutations showed higher LDL-C (215.2 ± 52.7 mg/dL vs 181.0 ± 44.6 mg/dL, P <.001) and apolipoprotein B levels (131.6 ± 38.3 mg/dL vs 100.3 ± 30.0 mg/dL, P <.004), compared with noncarriers. A LDL-C of ~190 mg/dL was the optimal value to discriminate children with and without LDLR mutations. When different diagnostic criteria were compared, those proposed by the European Atherosclerosis Society showed a reasonable balance between sensitivity and specificity in the identification of LDLR mutations. In children without mutation, the FH phenotype was not caused by the aggregation of LDL-C raising single-nucleotide polymorphisms.

CONCLUSIONS

In unselected children with hypercholesterolemia, LDL-C levels >190 mg/dL and a positive family history of hypercholesterolemia appeared to be the most reliable criteria for detecting FH. As 50% of children with suspected FH did not carry FH-causing mutations, genetic testing should be considered.

Genotype-guided diagnosis in familial hypercholesterolemia: population burden and cascade screening

PURPOSE OF REVIEW

In this review, how genetic testing has provided major new insights regarding the population burden of familial hypercholesterolemia (FH) are reviewed. In addition, the role of genetic testing in cascade screening for FH and an updated MEDPED (Make Early Diagnoses to Prevent Early Death in MEDical PEDigrees) algorithm for the clinical diagnosis of FH are presented.

RECENT FINDINGS

For the first time, recent application of genetic testing for FH in large populations has provided firm estimates of the prevalence of FH (at least one in 220) in the USA. High associated risks of coronary artery disease make FH the most common genetic cause of premature coronary artery disease.

SUMMARY

Genetic testing has yielded accurate, new estimates of the population burden of FH. The potential benefits of early diagnosis of FH on a population-wide level have not yet begun to be realized.

A novel approach to screening for familial hypercholesterolemia in a large public venue

The primary aim of this study was to test the feasibility of a public health screening program to identify individuals at high risk of familial hypercholesterolemia through a novel screening approach at a large public venue. A finger-prick, non-fasting lipid panel was obtained, and a survey which consisted of 44 open- and close-ended questions divided into four sections: medical and family history of FH, opinions of cascade genetic testing, patient activation, and demographics was completed. A total of 971 participants met criteria and completed a cholesterol screen. In total, five individuals met either the Simon Broome Register or the Dutch Lipid Clinic Network criteria for possible familial hypercholesterolemia. Participants were generally positive towards genetic testing, and the vast majority listed they had no barriers to communication of genetic testing information to family members. However, the most common barrier listed was lack of communication skills. Our results suggest that a public health screening program for FH is viable at a large public venue. We argue that further research is needed to expand this study to a fully operational screening program.

The panorama of familial hypercholesterolemia in Latin America: a systematic review

The burden caused by familial hypercholesterolemia (FH) varies among countries and ethnic groups. The prevalence and characteristics of FH in Latin American (LA) countries is largely unknown. We present a systematic review (following the PRISMA statement) of FH in LA countries. The epidemiology, genetics, screening, management, and unique challenges encountered in these countries are discussed. Published reports discussing FH in Hispanic or LA groups was considered for analysis. Thirty studies were included representing 10 countries. The bulk of the data was generated in Brazil and Mexico. Few countries have registries and there was little commonality in FH mutations between LA countries. LDL receptor mutations predominate; APOB and PCSK9 mutations are rare. No mutation was found in an FH gene in nearly 50% of cases. In addition, some country-specific mutations have been reported. Scant information exists regarding models of care, cascade screening, cost, treatment effectiveness, morbidity, and mortality. In conclusion, FH is largely underdiagnosed and undertreated in the LA region. The genetic admixture with indigenous populations, producing mestizo's groups, may influence the mutational findings in Latin America. Potential opportunities to close gaps in knowledge and health care are identified.

National Lipid Association Annual Summary of Clinical Lipidology 2016

The National Lipid Association (NLA) Annual Summary of Clinical Lipidology is a yearly updated summary of principles important to the patient-centered evaluation, management, and care of patients with dyslipidemia. This summary is intended to be a "living document," with future annual updates based on emerging science, clinical considerations, and new NLA Position, Consensus, and Scientific Statements, thus providing an ongoing resource that applies the latest in medical science towards the clinical management of patients with dyslipidemia. Topics include the NLA Recommendations for Patient-Centered Management of Dyslipidemia, genetics, Familial Hypercholesterolemia, secondary causes of dyslipidemia, biomarkers and advanced lipid testing, nutrition, physical activity, obesity, adiposopathy, metabolic syndrome, diabetes mellitus, lipid pharmacotherapy, lipid-altering drug interactions, lipoprotein apheresis, dyslipidemia management and treatment based upon age (children, adolescents, and older individuals), dyslipidemia considerations based upon race, ethnicity and gender, dyslipidemia and human immune virus infection, dyslipidemia and immune disorders, adherence strategies and collaborative care, and lipid-altering drugs in development. Hyperlinks direct the reader to sentinel online tables, charts, and figures relevant to lipidology, access to online atherosclerotic cardiovascular disease risk calculators, worldwide lipid guidelines, recommendations, and position/scientific statements, as well as links to online audio files, websites, slide shows, applications, continuing medical education opportunities, and patient information.

Dementia Improvement after Plasma Exchange for Familial Hypercholesterolemia

Worldwide dementia related memory issues affect a great number of patients and families. In this case, a "senior moment" was noted at age fifty and issues with memory and mind progressed resulting in early retirement from work. The patient described here was given a diagnosis of "Pre-Alzheimer's disease" and presented for further accurate evaluation, diagnosis, and management. The medical management resulted in an improvement in the patients memory and cognitive ability.

Therapeutic Management of Familial Hypercholesterolemia: Current and Emerging Drug Therapies

Familial hypercholesterolemia (FH) is a genetic disorder characterized by significantly elevated low-density lipoprotein cholesterol (LDL-C) concentrations that result from mutations of the LDL receptor, apolipoprotein B (apo B-100), and proprotein convertase subtilisin/kexin type 9 (PCSK9). Early and aggressive treatment can prevent premature atherosclerotic cardiovascular disease in these high-risk patients. Given that the cardiovascular consequences of FH are similar to typical hypercholesterolemia, traditional therapies are utilized to decrease LDL-C levels. Patients with FH should receive statins as first-line treatment; high-potency statins at high doses are often required. Despite the use of statins, additional treatments are often necessary to achieve appropriate LDL-C lowering in this patient population. Novel drug therapies that target the pathophysiologic defects of the condition are continuously emerging. Contemporary therapies including mipomersen (Kynamro, Genzyme), an oligonucleotide inhibitor of apo B-100 synthesis; lomitapide (Juxtapid, Aegerion), a microsomal triglyceride transfer protein inhibitor; and alirocumab (Praluent, Sanofi-Aventis/Regeneron) and evolocumab (Repatha, Amgen), PCSK9 inhibitors, are currently approved by the U.S. Food and Drug Administration for use in FH. This review highlights traditional as well as emerging contemporary therapies with supporting clinical data to evaluate current recommendations and discuss the future direction of FH management.

New Approaches in Detection and Treatment of Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is an autosomal dominant genetic disorder that clinically leads to increased low density lipoprotein-cholesterol (LDL-C) levels. As a consequence, FH patients are at high risk for cardiovascular disease (CVD). Mutations are found in genes coding for the LDLR, apoB, and PCSK9, although FH cannot be ruled out in the absence of a mutation in one of these genes. It is pivotal to diagnose FH at an early age, since lipid lowering results in a decreased risk of cardiovascular complications especially if initiated early, but unfortunately FH is largely underdiagnosed. While a number of clinical criteria are available, identification of a pathogenic mutation in any of the three aforementioned genes is seen by many as a way to establish a definitive diagnosis of FH. It should be remembered that clinical treatment is based on LDL-C levels and not solely on presence or absence of genetic mutations as LDL-C is what drives risk. Traditionally, mutation detection has been done by means of dideoxy sequencing. However, novel molecular testing methods are gradually being introduced. These next generation sequencing-based methods are likely to be applied on broader scale once their efficacy and effect on cost are being established. Statins are the first-line therapy of choice for FH patients as they have been proven to reduce CVD risk across a range of conditions including hypercholesterolemia (though not specifically tested in FH). However, in a significant proportion of FH patients LDL-C goals are not met, despite the use of maximal statin doses and additional lipid-lowering therapies. This underlines the need for additional therapies, and inhibition of PCSK9 and CETP is among the most promising new therapeutic options. In this review, we aim to provide an overview of the latest information about the definition, diagnosis, screening, and current and novel therapies for FH.

US physician practices for diagnosing familial hypercholesterolemia: data from the CASCADE-FH registry

BACKGROUND

In the US familial hypercholesterolemia (FH), patients are underidentified, despite an estimated prevalence of 1:200 to 1:500. Criteria to identify FH patients include Simon Broome, Dutch Lipid Clinic Network (DLCN), or Make Early Diagnosis to Prevent Early Deaths (MEDPED). The use of these criteria in US clinical practices remains unclear.

OBJECTIVE

To characterize the FH diagnostic criteria applied by US lipid specialists participating in the FH Foundation's CASCADE FH (CAscade SCreening for Awareness and DEtection of Familial Hypercholesterolemia) patient registry.

METHODS

We performed an observational, cross-sectional analysis of diagnostic criteria chosen for each adult patient, both overall and by baseline patient characteristics, at 15 clinical sites that had contributed data to the registry as of September 8, 2015. A sample of 1867 FH adults was analyzed. The median age at FH diagnosis was 50 years, and the median pretreatment low-density lipoprotein cholesterol (LDL-C) value was 238 mg/dL. The main outcome was the diagnostic criteria chosen. Diagnostic criteria were divided into five nonexclusive categories: "clinical diagnosis," MEDPED, Simon Broome, DLCN, and other.

RESULTS

Most adults enrolled in CASCADE FH (55.0%) received a "clinical diagnosis." The most commonly used formal criteria was Simon-Broome only (21%), followed by multiple diagnostic criteria (16%), MEDPED only (7%), DLCN only (1%), and other (0.5%), P < .0001. Of the patients with only a "clinical diagnosis," 93% would have met criteria for Simon Broome, DLCN, or MEDPED based on the data available in the registry.

CONCLUSIONS

Our findings demonstrate heterogeneity in the application of FH diagnostic criteria in the United States. A nationwide consensus definition may lead to better identification, earlier treatment, and ultimately CHD prevention.

Dutch Lipid Clinic Network low-density lipoprotein cholesterol criteria are associated with long-term mortality in the general population

BACKGROUND

Heterozygous familial hypercholesterolaemia (HeFH) is a severe autosomal dominant disease that is underdiagnosed, inadequately treated and has a severe long-term cardiovascular risk. Few studies have evaluated the long-term risk of high low-density lipoprotein cholesterol (LDL-C) concentrations.

AIM

To evaluate long-term mortality in a large cohort of healthy subjects, according to LDL-C concentrations.

METHODS

Based on a sample of 6956 subjects visiting a preventive cardiology department, we selected adult subjects without a personal history of cardiovascular disease. From 1995 to 2011, 4930 healthy subjects were examined and followed up until 31 December 2011. All-cause deaths were collected exhaustively. A Cox-based multivariable analysis evaluated long-term total mortality risk according to Dutch Lipid Clinic Network (DLCN) LDL-C concentrations.

RESULTS

After a mean follow-up of 8.6 years, 123 all-cause deaths were recorded (cumulative mortality rate, 2.5%). In the final multivariable model, major risk factors such as age, sex, tobacco use and diabetes were significantly associated with mortality. After adjustment for age, sex, tobacco use, hypertension, diabetes and statin therapy, and in comparison with subjects with LDL-C<4 mmol/L (<155 mg/dL), subjects with LDL-C between 4 and <5 mmol/L (155 to <190 mg/dL) had a hazard ratio (HR) of 1.99 (95% confidence interval [CI] 1.31-3.02; P=0.001), subjects with LDL-C between 5 and <6.5 mmol/L (190 to <250 mg/dL) had an HR of 1.81 (95% CI, 1.06-3.02; P=0.030), subjects with LDL-C between 6.5 and<8.5 mmol/L (250 to <330 mg/dL) had an HR of 2.69 (95% CI, 1.06-6.88; P=0.038) and subjects with LDL-C ≥ 8.5 mmol/L (≥330 mg/dL) had an HR of 6.27 (95% CI, 0.84-46.57; P=0.073). After excluding patients on statins at baseline, subjects with LDL-C ≥ 8.5 mmol/L (≥330 mg/dL) had an HR of 8.17 (95% CI, 1.08-62.73; P=0.042).

CONCLUSIONS

The severity of LDL-C elevation is associated with a higher risk of death in healthy subjects. DLCN LDL-C concentrations may be used in daily practice to identify patients with HeFH who warrant aggressive treatment.

Diagnostic scoring for familial hypercholesterolaemia in practice

PURPOSE OF REVIEW

Diagnostic scoring for familial hypercholesterolaemia (FH) can be used either to screen for possible FH or guide the selection of patients for genetic (DNA) testing. We review the published diagnostic criteria and discuss the options for future development.

RECENT FINDINGS

Scoring systems have been developed internationally based on lipid values and various combinations of clinical signs and cardiovascular history. The predictive value varies according to the test population, be it lipid clinic referrals, general population, or relatives of patients with FH. Also, there is increasing recognition of genetic heterogeneity in FH so that criteria are of differing predictive value depending on the genetic variant of FH.

SUMMARY

These clinical scoring systems are increasingly used to guide selection of patients for FH genetic testing but no single approach has yet emerged as the system of choice. Further refinement of these scoring tools using more sophisticated calculators are superseding the more manual approaches. These are well suited to web-based tools or smartphone applications.

Identification and Treatment of Patients with Homozygous Familial Hypercholesterolaemia: Information and Recommendations from a Middle East Advisory Panel

We present clinical practice guidelines for the diagnosis and treatment of homozygous familial hypercholesterolaemia (HoFH) in the Middle East region. While guidelines are broadly applicable in Europe, in the Middle East we experience a range of confounding factors that complicate disease management to a point whereby the European guidance cannot be applied without significant modification. Specifically, for disease prevalence, the Middle East region has an established epidemic of diabetes and metabolic syndrome that can complicate treatment and mask a clinical diagnosis of HoFH. We have also a high incidence of consanguineous marriages, which increase the risk of transmission of recessive and homozygous genetic disorders. This risk is further augmented in autosomal dominant disorders such as familial 
hypercholesterolaemia (FH), in which a range of defective genes can be transmitted, all of which contribute to the phenotypic expression of the disease. In terms of treatment, we do not have access to lipoprotein apheresis on the same scale as in Europe, and there remains a significant reliance on statins, ezetimibe and the older plasma exchange methods. Additionally, we do not have widespread access to anti-apolipoprotein B therapies and microsomal transfer protein inhibitors. In order to adapt existing global guidance documents on HoFH to the Middle East region, we convened a panel of experts from Oman, Saudi Arabia, UAE, Iran and Bahrain to draft a regional guidance document for HoFH. We also included selected experts from outside the region. This panel statement will form the foundation of a detailed appraisal of the current FH management in the Middle Eastern population and thereby provide a suitable set of guidelines tailored for the region.

Long-Term Risk of Atherosclerotic Cardiovascular Disease in US Adults With the Familial Hypercholesterolemia Phenotype

BACKGROUND

Heterozygous familial hypercholesterolemia (FH) affects up to 1 in 200 individuals in the United States, but atherosclerotic cardiovascular disease (ASCVD) outcomes of FH in the general US population have not been described. We therefore sought to evaluate long-term coronary heart disease (CHD) and total ASCVD risks in US adults with an FH phenotype.

METHODS

Using individual pooled data from 6 large US epidemiological cohorts, we stratified participants by low-density lipoprotein cholesterol level at index ages from 20 to 79 years. For the primary analysis, low-density lipoprotein cholesterol levels ≥190 and <130 mg/dL defined the FH phenotype and referent, respectively. Sensitivity analyses evaluated the effects of varying the FH phenotype definition. We used Cox regression models to assess covariate-adjusted associations of the FH phenotype with 30-year hazards for CHD (CHD death or nonfatal myocardial infarction) and total ASCVD (CHD or stroke).

RESULTS

We included 68 565 baseline person-examinations; 3850 (5.6%) had the FH phenotype by the primary definition. Follow-up across index ages ranged from 78 985 to 308 378 person-years. After covariate adjustment, the FH phenotype was associated with substantially elevated 30-year CHD risk, with hazard ratios up to 5.0 (95% confidence interval, 1.1-21.7). Across index ages, CHD risk was accelerated in those with the FH phenotype by 10 to 20 years in men and 20 to 30 years in women. Similar patterns of results were found for total ASCVD risk, with hazard ratios up to 4.1 (95% confidence interval, 1.2-13.4). Alternative FH phenotype definitions incorporating family history, more stringent age-based low-density lipoprotein cholesterol thresholds, or alternative lipid fractions decreased the FH phenotype prevalence to as low as 0.2% to 0.4% without materially affecting CHD risk estimates (hazard ratios up to 8.0; 95% confidence interval, 1.0-61.6).

CONCLUSIONS

In the general US population, the long-term ASCVD burden related to phenotypic FH, defined by low-density lipoprotein cholesterol ≥190 mg/dL, is likely substantial. Our finding of CHD risk acceleration may aid efforts in risk communication.

High lipoprotein(a) as a possible cause of clinical familial hypercholesterolaemia: a prospective cohort study

BACKGROUND

The reason why lipoprotein(a) concentrations are raised in individuals with clinical familial hypercholesterolaemia is unclear. We tested the hypotheses that high lipoprotein(a) cholesterol and LPA risk genotypes are a possible cause of clinical familial hypercholesterolaemia, and that individuals with both high lipoprotein(a) concentrations and clinical familial hypercholesterolaemia have the highest risk of myocardial infarction.

METHODS

We did a prospective cohort study that included data from 46 200 individuals from the Copenhagen General Population Study who had lipoprotein(a) measurements and were genotyped for common familial hypercholesterolaemia mutations. Individuals receiving cholesterol-lowering drugs had their concentrations of LDL and total cholesterol multiplied by 1·43, corresponding to an estimated 30% reduction in LDL cholesterol from the treatment. In lipoprotein(a) cholesterol-adjusted analyses, total cholesterol and LDL cholesterol were adjusted for the lipoprotein(a) cholesterol content by subtracting 30% of the individuals' lipoprotein(a) total mass before total and LDL cholesterol were used for diagnosis of clinical familial hypercholesterolaemia. We used modified Dutch Lipid Clinic Network (DLCN), Simon Broome, and Make Early Diagnosis to Prevent Early Death (MEDPED) criteria to clinically diagnose familial hypercholesterolaemia. Cox proportional hazard regression calculated hazard ratios (95% CI) of myocardial infarction.

FINDINGS

Using unadjusted LDL cholesterol, mean lipoprotein(a) concentrations were 23 mg/dL in individuals unlikely to have familial hypercholesterolaemia, 32 mg/dL in those with possible familial hypercholesterolaemia, and 35 mg/dL in those with probable or definite familial hypercholesterolaemia (ptrend<0·0001). However, when adjusting LDL cholesterol for lipoprotein(a) cholesterol content the corresponding values were 24 mg/dL for individuals unlikely to have familial hypercholesterolaemia, 22 mg/dL for those with possible familial hypercholesterolaemia, and 21 mg/dL for those with probable or definite familial hypercholesterolaemia (ptrend=0·46). High lipoprotein(a) cholesterol accounted for a quarter of all individuals diagnosed with clinical familial hypercholesterolaemia and LPA risk genotypes were more frequent in clinical familial hypercholesterolaemia, whereas lipoprotein(a) concentrations were similar in those with and without familial hypercholesterolaemia mutations. The hazard ratios (HRs) for myocardial infarction compared with individuals unlikely to have familial hypercholesterolaemia and lipoprotein(a) concentration of 50 mg/dL or less were 1·4 (95% CI 1·1-1·7) in those unlikely to have familial hypercholesterolaemia and lipoprotein(a) concentrations of more than 50 mg/dL, 3·2 (2·5-4·1) in those with possible, probable, or definite familial hypercholesterolaemia and lipoprotein(a) concentration of 50 mg/dL or less, and 5·3 (3·6-7·6) in those with possible, probable, or definite familial hypercholesterolaemia and lipoprotein(a) concentration of more than 50 mg/dL. In analyses using Simon Broome or MEDPED criteria, results were similar to those using DLCN criteria to diagnose clinical familial hypercholesterolaemia.

INTERPRETATION

High lipoprotein(a) concentrations and corresponding LPA risk genotypes represent novel risk factors for clinical familial hypercholesterolaemia. Our findings suggest that all individuals with familial hypercholesterolaemia should have their lipoprotein(a) measured in order to identify those with the highest concentrations, and as a result, the highest risk of myocardial infarction.

FUNDING

Danish Heart Association and IMK General Fund, Denmark.

The genetics and screening of familial hypercholesterolaemia

Familial Hypercholesterolaemia is an autosomal, dominant genetic disorder that leads to elevated blood cholesterol and a dramatically increased risk of atherosclerosis. It is perceived as a rare condition. However it affects 1 in 250 of the population globally, making it an important public health concern. In communities with founder effects, higher disease prevalences are observed.

We discuss the genetic basis of familial hypercholesterolaemia, examining the distribution of variants known to be associated with the condition across the exons of the genes LDLR, ApoB, PCSK9 and LDLRAP1. We also discuss screening programmes for familial hypercholesterolaemia and their cost-effectiveness. Diagnosis typically occurs using one of the Dutch Lipid Clinic Network (DCLN), Simon Broome Register (SBR) or Make Early Diagnosis to Prevent Early Death (MEDPED) criteria, each of which requires a different set of patient data. New cases can be identified by screening the family members of an index case that has been identified as a result of referral to a lipid clinic in a process called cascade screening. Alternatively, universal screening may be used whereby a population is systematically screened.

It is currently significantly more cost effective to identify familial hypercholesterolaemia cases through cascade screening than universal screening. However, the cost of sequencing patient DNA has fallen dramatically in recent years and if the rate of progress continues, this may change.

Treatment Gaps in Adults With Heterozygous Familial Hypercholesterolemia in the United States: Data From the CASCADE-FH Registry

BACKGROUND

Cardiovascular disease burden and treatment patterns among patients with familial hypercholesterolemia (FH) in the United States remain poorly described. In 2013, the FH Foundation launched the Cascade Screening for Awareness and Detection (CASCADE) of FH Registry to address this knowledge gap.

METHODS AND RESULTS

We conducted a cross-sectional analysis of 1295 adults with heterozygous FH enrolled in the CASCADE-FH Registry from 11 US lipid clinics. Median age at initiation of lipid-lowering therapy was 39 years, and median age at FH diagnosis was 47 years. Prevalent coronary heart disease was reported in 36% of patients, and 61% exhibited 1 or more modifiable risk factors. Median untreated low-density lipoprotein cholesterol (LDL-C) was 239 mg/dL. At enrollment, median LDL-C was 141 mg/dL; 42% of patients were taking high-intensity statin therapy and 45% received >1 LDL-lowering medication. Among FH patients receiving LDL-lowering medication(s), 25% achieved an LDL-C <100 mg/dL and 41% achieved a ≥50% LDL-C reduction. Factors associated with prevalent coronary heart disease included diabetes mellitus (adjusted odds ratio 1.74; 95% confidence interval 1.08-2.82) and hypertension (2.48; 1.92-3.21). Factors associated with a ≥50% LDL-C reduction from untreated levels included high-intensity statin use (7.33; 1.86-28.86) and use of >1 LDL-lowering medication (1.80; 1.34-2.41).

CONCLUSIONS

FH patients in the CASCADE-FH Registry are diagnosed late in life and often do not achieve adequate LDL-C lowering, despite a high prevalence of coronary heart disease and risk factors. These findings highlight the need for earlier diagnosis of FH and initiation of lipid-lowering therapy, more consistent use of guideline-recommended LDL-lowering therapy, and comprehensive management of traditional coronary heart disease risk factors.

Prevalence of Familial Hypercholesterolemia in the 1999 to 2012 United States National Health and Nutrition Examination Surveys (NHANES)

Background—

The prevalence of familial hypercholesterolemia (FH) is commonly reported as 1 in 500. European reports suggest a higher prevalence; the US FH prevalence is unknown.

Methods and Results—

The 1999 to 2012 National Health and Nutrition Examination Survey (NHANES) participants ≥20 years of age (n=36 949) were analyzed to estimate the prevalence of FH with available Dutch Lipid Clinic criteria, including low-density lipoprotein cholesterol and personal and family history of premature atherosclerotic cardiovascular disease. Prevalence and confidence intervals of probable/definite FH were calculated for the overall population and by age, sex, obesity status (body mass index ≥30 kg/m 2 ), and race/ethnicity. Results were extrapolated to the 210 million US adults ≥20 years of age. The estimated overall US prevalence of probable/definite FH was 0.40% (95% confidence interval, 0.32–0.48) or 1 in 250 (95% confidence interval, 1 in 311 to 209), suggesting that 834 500 US adults have FH. Prevalence varied by age, being least common in 20 to 29 year olds (0.06%, 1 in 1557) and most common in 60 to 69 year olds (0.85%, 1 in 118). FH prevalence was similar in men and women (0.40%, 1 in 250) but varied by race/ethnicity (whites: 0.40%, 1 in 249; blacks: 0.47%, 1 in 211; Mexican Americans: 0.24%, 1 in 414; other races: 0.29%, 1 in 343). More obese participants qualified as probable/definite FH (0.58%, 1 in 172) than nonobese (0.31%, 1 in 325).

Conclusions—

FH, defined with Dutch Lipid Clinic criteria available in NHANES, affects 1 in 250 US adults. Variations in prevalence by age and obesity status suggest that clinical criteria may not be sufficient to estimate FH prevalence.

Genetic Testing in Hyperlipidemia

Hereditary dyslipidemias are often underdiagnosed and undertreated, yet with significant health implications, most importantly causing preventable premature cardiovascular diseases. The commonly used clinical criteria to diagnose hereditary lipid disorders are specific but are not very sensitive. Genetic testing may be of value in making accurate diagnosis and improving cascade screening of family members, and potentially, in risk assessment and choice of therapy. This review focuses on using genetic testing in the clinical setting for lipid disorders, particularly familial hypercholesterolemia.

Familial Hypercholesterolemia

Familial hypercholesterolemia is a common, inherited disorder of cholesterol metabolism that leads to early cardiovascular morbidity and mortality. It is underdiagnosed and undertreated. Statins, ezetimibe, bile acid sequestrants, niacin, lomitapide, mipomersen, and low-density lipoprotein (LDL) apheresis are treatments that can lower LDL cholesterol levels. Early treatment can lead to substantial reduction of cardiovascular events and death in patients with familial hypercholesterolemia. It is important to increase awareness of this disorder in physicians and patients to reduce the burden of this disorder.

Are Genetic Tests for Atherosclerosis Ready for Routine Clinical Use?

In this review, we lay out 3 areas currently being evaluated for incorporation of genetic information into clinical practice related to atherosclerosis. The first, familial hypercholesterolemia, is the clearest case for utility of genetic testing in diagnosis and potentially guiding treatment. Already in use for confirmatory testing of familial hypercholesterolemia and for cascade screening of relatives, genetic testing is likely to expand to help establish diagnoses and facilitate research related to most effective therapies, including new agents, such as PCSK9 inhibitors. The second area, adding genetic information to cardiovascular risk prediction for primary prevention, is not currently recommended. Although identification of additional variants may add substantially to prediction in the future, combining known variants has not yet demonstrated sufficient improvement in prediction for incorporation into commonly used risk scores. The third area, pharmacogenetics, has utility for some therapies today. Future utility for pharmacogenetics will wax or wane depending on the nature of available drugs and therapeutic strategies.

Familial hypercholesterolemia

Familial hypercholesterolemia is a common, inherited disorder of cholesterol metabolism that leads to early cardiovascular morbidity and mortality. It is underdiagnosed and undertreated. Statins, ezetimibe, bile acid sequestrants, niacin, lomitapide, mipomersen, and low-density lipoprotein (LDL) apheresis are treatments that can lower LDL cholesterol levels. Early treatment can lead to substantial reduction of cardiovascular events and death in patients with familial hypercholesterolemia. It is important to increase awareness of this disorder in physicians and patients to reduce the burden of this disorder.

Global molecular analysis and APOE mutations in a cohort of autosomal dominant hypercholesterolemia patients in France

Autosomal dominant hypercholesterolemia (ADH) is a human disorder characterized phenotypically by isolated high-cholesterol levels. Mutations in the low density lipoprotein receptor (LDLR), APOB, and proprotein convertase subtilisin/kexin type 9 (PCSK9) genes are well known to be associated with the disease. To characterize the genetic background associated with ADH in France, the three ADH-associated genes were sequenced in a cohort of 120 children and 109 adult patients. Fifty-one percent of the cohort had a possible deleterious variant in LDLR, 3.1% in APOB, and 1.7% in PCSK9. We identified 18 new variants in LDLR and 2 in PCSK9. Three LDLR variants, including two newly identified, were studied by minigene reporter assay confirming the predicted effects on splicing. Additionally, as recently an in-frame deletion in the APOE gene was found to be linked to ADH, the sequencing of this latter gene was performed in patients without a deleterious variant in the three former genes. An APOE variant was identified in three patients with isolated severe hypercholesterolemia giving a frequency of 1.3% in the cohort. Therefore, even though LDLR mutations are the major cause of ADH with a large mutation spectrum, APOE variants were found to be significantly associated with the disease. Furthermore, using structural analysis and modeling, the identified APOE sequence changes were predicted to impact protein function.