Familial Chylomicronemia Syndrome (FCS): Recent Data on Diagnosis and Treatment

Angiopoietin-like Proteins and Lipoprotein Lipase: The Waltz Partners That Govern Triglyceride-Rich Lipoprotein Metabolism? Impact on Atherogenesis, Dietary Interventions, and Emerging Therapies

Over 50% of patients who take statins are still at risk of developing atherosclerotic cardiovascular disease (ASCVD) and do not achieve their goal LDL-C levels. This residual risk is largely dependent on triglyceride-rich lipoproteins (TRL) and their remnants. In essence, remnant cholesterol-rich chylomicron (CM) and very-low-density lipoprotein (VLDL) particles play a role in atherogenesis. These remnants increase when lipoprotein lipase (LPL) activity is inhibited. ApoCIII has been thoroughly studied as a chief inhibitor and therapeutic options to curb its effect are available. On top of apoCIII regulation of LPL activity, there is a more precise control of LPL in various tissues, which makes it easier to physiologically divide the TRL burden according to the body's requirements. In general, oxidative tissues such as skeletal and cardiac muscle preferentially take up lipids during fasting. Conversely, LPL activity in adipocytes increases significantly after feeding, while its activity in oxidative tissues decreases concurrently. This perspective addresses the recent improvements in our understanding of circadian LPL regulations and their therapeutic implications. Three major tissue-specific lipolysis regulators have been identified: ANGPTL3, ANGPTL4, and ANGPTL8. Briefly, during the postprandial phase, liver ANGPTL8 acts on ANGPTL3 (which is released continuously from the liver) to inhibit LPL in the heart and muscle through an endocrine mechanism. On the other hand, when fasting, ANGPTL4, which is released by adipocytes, inhibits lipoprotein lipase in adipose tissue in a paracrine manner. ANGPTL3 inhibitors may play a therapeutic role in the treatment of hypertriglyceridemia. Several approaches are under development. We look forward to future studies to clarify (a) the nature of hormonal and nutritional factors that determine ANGPTL3, 4, and 8 activities, along with what long-term impacts may be expected if their regulation is impaired pharmacologically; (b) the understanding of the quantitative hierarchy and interaction of the regulatory actions of apoCIII, apoAV, and ANGPTL on LPL activity; (c) strategies for the safe and proper treatment of postprandial lipemia; and (d) the effect of fructose restriction on ANGPTL3, ANGPTL4, and ANGPTL8.

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.

Severe Hypertriglyceridemia in Patients with Type 2 Diabetes Mellitus Participating in the AMD Annals Initiative

Background: Familial chylomicronemia syndrome (FCS) is a rare inherited condition due to lipoprotein lipase deficiency, characterized by hyperchylomicronemia and severe hypertriglyceridemia. Diagnosis is often delayed, thus increasing the risk of acute pancreatitis and hospitalization. Hypertriglyceridemia is a common finding in patients with type 2 diabetes (T2D), who may harbor FCS among the most severe forms. Aim of the Study: We investigated the prevalence and clinical characteristics associated with severe hypertriglyceridemia in a range indicative of FCS, in a large population of subjects with T2D. Methods: Within the large population of the AMD Annals Initiative, patients with T2D with a lipid profile suggestive of FCS [triglycerides >880 mg/dL and/or high-density lipoprotein (HDL)-cholesterol <22 mg/dL or non-HDL-cholesterol ≤70 mg/dL] and their clinical features have been identified. Results: Overall, 8592 patients had triglyceride values >880 mg/dL in a single examination, 613 in two examinations, and 34 in three or more measurements. Patients with high triglyceride levels were mostly male (80%), with a relatively young age (54 years), short duration of diabetes (6.3 years), and elevated hemoglobin A1c (HbA1c) levels (9.4%). By stratifying this group of patients according to the severity of hypertriglyceridemia, more severe hypertriglyceridemia (triglyceride levels ≥2000 mg/dL) was associated with an even younger age (52 vs. 54 years), even higher mean HbA1c values (10.0% vs. 9.4%), and significantly higher HDL-cholesterol levels (37.9 vs. 32.4 mg/dL; P < 0.0001). Patients with persistently elevated triglyceride levels (n = 34), on three measurements, had a younger age; lower body mass index, HbA1c, and HDL-cholesterol levels; more frequent use of fibrates and insulin; and a higher prevalence of major cardiovascular events. Conclusions: Severe hypertriglyceridemia is a frequent condition in outpatients with T2D participating in the AMD Annals Initiative, and it is associated with male sex, young age, short disease duration, and a worse glycemic profile. Among patients with persistent severe hypertriglyceridemia, hidden FCS may be present.

Long-term clinical outcomes and management of hypertriglyceridemia in children with Apo-CII deficiency

BACKGROUND AND AIM

APO CII, one of several cofactors which regulate lipoprotein lipase enzyme activity, plays an essential role in lipid metabolism. Deficiency of APO CII is an ultra-rare autosomal recessive cause of familial chylomicronemia syndrome. We present the long-term clinical outcomes of 12 children with APO CII deficiency.

METHODS AND RESULTS

The data of children with genetically confirmed APO CII deficiency were evaluated retrospectively. Twelve children (8 females) with a mean follow-up of 10.1 years (±3.9) were included. At diagnosis, the median age was 60 days (13 days-10 years). Initial clinical findings included lipemic serum (41.6%), abdominal pain (41.6%), and vomiting (16.6%). At presentation, the median triglyceride (TG) value was 4341 mg/dL (range 1277-14,110). All patients were treated with a restricted fat diet, medium-chain triglyceride (MCT), and omega-3-fatty acids. In addition, seven patients (58.3%) received fibrate. Fibrate was discontinued in two patients due to rhabdomyolysis and in one patient because of cholelithiasis. Seven (58.3%) patients experienced pancreatitis during the follow-up period. One female experienced recurrent pancreatitis and was treated with fresh frozen plasma (FFP).

CONCLUSIONS

Apo CII deficiency is an ultra-rare autosomal recessive condition of hypertriglyceridemia associated with significant morbidity and mortality. Low-fat diet and MCT supplementation are the mainstays of therapy, while the benefit of TG-lowering agents are less well-defined.

Hypertriglyceridemia: Molecular and Genetic Landscapes

Lipid disorders represent one of the most worrisome cardiovascular risk factors. The focus on the impact of lipids on cardiac and vascular health usually concerns low-density lipoprotein cholesterol, while the role of triglycerides (TGs) is given poor attention. The literature provides data on the impact of higher plasma concentrations in TGs on the cardiovascular system and, therefore, on the outcomes and comorbidities of patients. The risk for coronary heart diseases varies from 57 to 76% in patients with hypertriglyceridemia. Specifically, the higher the plasma concentrations in TGs, the higher the incidence and prevalence of death, myocardial infarction, and stroke. Nevertheless, the metabolism of TGs and the exact physiopathologic mechanisms which try to explain the relationship between TGs and cardiovascular outcomes are not completely understood. The aims of this narrative review were as follows: to provide a comprehensive evaluation of the metabolism of triglycerides and a possible suggestion for understanding the targets for counteracting hypertriglyceridemia; to describe the inner physiopathological background for the relationship between vascular and cardiac damages derived from higher plasma concentrations in TGs; and to outline the need for promoting further insights in therapies for reducing TGs plasma levels.

Understanding Hypertriglyceridemia: Integrating Genetic Insights

Hypertriglyceridemia is an exceptionally complex metabolic disorder characterized by elevated plasma triglycerides associated with an increased risk of acute pancreatitis and cardiovascular diseases such as coronary artery disease. Its phenotype expression is widely heterogeneous and heavily influenced by conditions as obesity, alcohol consumption, or metabolic syndromes. Looking into the genetic underpinnings of hypertriglyceridemia, this review focuses on the genetic variants in LPL, APOA5, APOC2, GPIHBP1 and LMF1 triglyceride-regulating genes reportedly associated with abnormal genetic transcription and the translation of proteins participating in triglyceride-rich lipoprotein metabolism. Hypertriglyceridemia resulting from such genetic abnormalities can be categorized as monogenic or polygenic. Monogenic hypertriglyceridemia, also known as familial chylomicronemia syndrome, is caused by homozygous or compound heterozygous pathogenic variants in the five canonical genes. Polygenic hypertriglyceridemia, also known as multifactorial chylomicronemia syndrome in extreme cases of hypertriglyceridemia, is caused by heterozygous pathogenic genetic variants with variable penetrance affecting the canonical genes, and a set of common non-pathogenic genetic variants (polymorphisms, using the former nomenclature) with well-established association with elevated triglyceride levels. We further address recent progress in triglyceride-lowering treatments. Understanding the genetic basis of hypertriglyceridemia opens new translational opportunities in the scope of genetic screening and the development of novel therapies.

The chylomicron saga: time to focus on postprandial metabolism

Since statins have had such tremendous therapeutic success over the last three decades, the field of atherosclerosis has become somewhat LDL-centric, dismissing the relevance of triglycerides (TG), particularly chylomicrons, in atherogenesis. Nonetheless, 50% of patients who take statins are at risk of developing atherosclerotic cardiovascular disease (ASCVD) and are unable to achieve their goal LDL-C levels. This residual risk is mediated, in part by triglyceride rich lipoproteins (TRL) and their remnants. Following his seminal investigation on the subject, Zilversmit proposed that atherosclerosis is a postprandial event in 1979 (1-4). In essence, the concept suggests that remnant cholesterol-rich chylomicron (CM) and very-low density lipoprotein (VLDL) particles play a role in atherogenesis. Given the foregoing, this narrative review addresses the most recent improvements in our understanding of postprandial dyslipidemia. The primary metabolic pathways of chylomicrons are discussed, emphasizing the critical physiological role of lipoprotein lipase and apoCIII, the importance of these particles' fluxes in the postprandial period, their catabolic rate, the complexities of testing postprandial metabolism, and the role of angiopoietin-like proteins in the partition of CM during the fed cycle. The narrative is rounded out by the dysregulation of postprandial lipid metabolism in insulin resistance states and consequent CVD risk, the clinical evaluation of postprandial dyslipidemia, current research limits, and potential future study directions.

Clinical profile, genetic spectrum and therapy evaluation of 19 Chinese pediatric patients with lipoprotein lipase deficiency

BACKGROUND

Lipoprotein lipase (LPL) deficiency, the most common familial chylomicronemia syndrome (FCS), is a rare autosomal recessive disease characterized by chylomicronemia and severe hypertriglyceridemia (HTG), with limited clinical and genetic characterization.

OBJECTIVE

To describe the manifestations and management of 19 pediatric patients with LPL-FCS.

METHODS

LPL-FCS patients from 2014 to 2022 were divided into low-fat (LF), very-low-fat (VLF) and medium-chain-triglyceride (MCT) groups. Their clinical data were evaluated to investigate the effect of different diets. The genotype-phenotype relationship was assessed. Linear regression comparing long-chain triglyceride (LCT) intake and TG levels was analyzed.

RESULTS

Nine novel LPL variants were identified in 19 LPL-FCS pediatric patients. At baseline, eruptive xanthomas occurred in 3/19 patients, acute pancreatitis in 2/19, splenomegaly in 6/19 and hepatomegaly in 3/19. The median triglyceride (TG) level (30.3 mmol/L) was markedly increased. The MCT group and VLF group with LCT intakes <20 en% (energy percentage) had considerably lower TG levels than the LF group (both p<0.05). The LF group presented with severe HTG and significantly decreased TG levels after restricting LCT intakes to <20 en% (p<0.05). Six infants decreased TG levels to <10 mmol/L by keeping LCT intake <10 en%. TG levels and LCT intake were positively correlated in both patients under 2 years (r=0.84) and those aged 2-9 years (r=0.89). No genotype-phenotype relationship was observed.

CONCLUSIONS

This study broadens the clinical and genetic spectra of LPL-FCS. The primary therapy for LPL-FCS pediatric patients is restricting dietary LCTs to <10 en% or <20 en% depending on different ages. MCTs potentially provide extra energy.

Sugar and Dyslipidemia: A Double-Hit, Perfect Storm

The availability of sugar has expanded over the past 50 years, due to improved industrial processes and corn subsidies, particularly in the form of sweetened beverages. This correlates with a surge in the prevalence of cardiometabolic disorders, which has brought this issue back into the spotlight for public health. In this narrative review, we focus on the role of fructose in the genesis of cardiometabolic dyslipidemia (an increase in serum triglyceride-rich lipoproteins (TRL): VLDL, chylomicrons (CM), and their remnants) bringing together the most recent data on humans, which demonstrates the crucial interaction between glucose and fructose, increasing the synthesis while decreasing the catabolism of these particles in a synergistic downward spiral. After reviewing TRL metabolism, we discuss the fundamental principles governing the metabolism of fructose in the intestine and liver and the effects of dysregulated fructolysis, in conjunction with the activation of carbohydrate-responsive element-binding protein (ChREBP) by glucose and the resulting crosstalk. The first byproduct of fructose catabolism, fructose-1-P, is highlighted for its function as a signaling molecule that promotes fat synthesis. We emphasize the role of fructose/glucose interaction in the liver, which enhances de novo lipogenesis, triglyceride (TG) synthesis, and VLDL production. In addition, we draw attention to current research that demonstrates how fructose affects the activity of lipoprotein lipase by increasing the concentration of inhibitors such as apolipoprotein CIII (apoCIII) and angiopoietin-like protein 3 (ANGPTL3), which reduce the catabolism of VLDL and chylomicrons and cause the building up of their atherogenic remnants. The end outcome is a dual, synergistic, and harmful action that encourages atherogenesis. Thus, considering the growing concerns regarding the connection between sugar consumption and cardiometabolic disease, current research strongly supports the actions of public health organizations aimed at reducing sugar intake, including dietary guidance addressing "safe" limits for sugar consumption.

Advances in Treatment of Dyslipidemia

Dyslipidemias have emerged as prevalent disorders among patients, posing significant risks for the development and progression of cardiovascular diseases. These conditions are characterized by elevated levels of total cholesterol (TC), triglycerides (TGs), and low-density lipoprotein cholesterol (LDL-C). This review delves into the current treatment approach, focusing on equalizing these parameters while enhancing the overall quality of life for patients. Through an extensive analysis of clinical trials, we identify disorders that necessitate alternative treatment strategies, notably familial hypercholesterolemia. The primary objective of this review is to consolidate existing information concerning drugs with the potential to revolutionize dyslipidemia management significantly. Among these promising pharmaceuticals, we highlight alirocumab, bempedoic acid, antisense oligonucleotides, angiopoietin-like protein inhibitors, apolipoprotein C-III (APOC3) inhibitors, lomitapide, and cholesterol ester transfer protein (CETP) inhibitors. Our review demonstrates the pivotal roles played by each of these drugs in targeting specific parameters of lipid metabolism. We outline the future landscape of dyslipidemia treatment, envisaging a more tailored and effective therapeutic approach to address this widespread medical concern.

Analyses of familial chylomicronemia syndrome in Pereira, Colombia 2010-2020: a cross-sectional study

BACKGROUND AND AIM

Familial chylomicronemia syndrome (FCS) is a rare autosomal recessive metabolic disorder caused by mutations in genes involved in chylomicron metabolism. On the other hand, multifactorial chylomicronemia syndrome (MCS) is a polygenic disorder and the most frequent cause of chylomicronemia, which results from the presence of multiple genetic variants related to chylomicron metabolism, in addition to secondary factors. Indeed, the genetic determinants that predispose to MCS are the presence of a heterozygous rare variant or an accumulation of several SNPs (oligo/polygenic). However, their clinical, paraclinical, and molecular features are not well established in our country. The objective of this study was to describe the development and results of a screening program for severe hypertriglyceridemia in Colombia.

METHODS

A cross-sectional study was performed. All patients aged >18 years with triglyceride levels ≥500 mg/dL from 2010 to 2020 were included. The program was developed in three stages: 1. Review of electronic records and identification of suspected cases based on laboratory findings (triglyceride levels ≥500 mg/dL); 2. Identification of suspected cases based on laboratory findings that also allowed us to exclude secondary factors; 3. Patients with FCS scores <8 were excluded. The remaining patients underwent molecular analysis.

RESULTS

In total, we categorized 2415 patients as suspected clinical cases with a mean age of 53 years, of which 68% corresponded to male patients. The mean triglyceride levels were 705.37 mg/dL (standard deviation [SD] 335.9 mg/dL). After applying the FCS score, 2.4% (n = 18) of patients met the probable case definition and underwent a molecular test. Additionally, 7 patients had unique variants in the APOA5 gene (c.694 T > C; p. Ser232Pro) or in the GPIHBP1 gene (c.523G > C; p. Gly175Arg), for an apparent prevalence of familial chylomicronemia in the consulting population of 0.41 per 1.000 patients with severe HTG measurement. No previously reported pathogenic variants were detected.

CONCLUSION

This study describes a screening program for the detection of severe hypertriglyceridemia. Although we identified seven patients as carriers of a variant in the APOA5 gene, we diagnosed only one patient with FCS. We believe that more programs of these characteristics should be developed in our region, given the importance of early detection of this metabolic disorder.

Hyperlipidemia and Cardiovascular Risk in Children and Adolescents

Atherosclerotic cardiovascular disease (ASCVD) represents the major cause of morbidity and mortality worldwide. The onset of the atherosclerosis process occurs during childhood and adolescence, subsequently leading to the onset of cardiovascular disease as young adults. Several cardiovascular risk factors can be identified in children and adolescents; however, hyperlipidemia, in conjunction with the global obesity epidemic, has emerged as the most prevalent, playing a key role in the development of ASCVD. Therefore, screening for hyperlipidemia is strongly recommended to detect high-risk children presenting with these disorders, as these patients deserve more intensive investigation and intervention. Treatment should be initiated as early as possible in order to reduce the risk of future ASCVD. In this review, we will discuss lipid metabolism and hyperlipidemia, focusing on correlations with cardiovascular risk and screening and therapeutic management to reduce or almost completely avoid the development of ASCVD.

Recent Apolipoprotein CIII trials

PURPOSE OF REVIEW

This review will briefly revise the evidence concerning the pharmacological inhibition of Apolipoprotein CIII (ApoCIII) in patients with hypertriglyceridemia.

RECENT FINDINGS

ApoCIII is a plasma apolipoprotein playing a major role in the metabolism of triglyceride-rich lipoproteins, namely chylomicrons and very-low-density lipoproteins as well as in the pathological processes involved in atherosclerosis. Therefore, ApoCIII is a potential new target for reducing plasma levels of TRLs and, thereby, cardiovascular risk. In recent years, there have been extensive preclinical and clinical pharmacological studies aimed at testing drugs directed against ApoCIII.

SUMMARY

In this review, firstly we will summarize the molecular function of ApoCIII in lipoprotein metabolism. Then, we will examine the lipid-lowering potential of the pharmacological inhibition of ApoCIII based on the results of clinical trial employing Volansesorsen, the first approved antisense therapeutic oligonucleotide against ApoCIII mRNA. The future perspectives for ApoCIII inhibition will be also revised.

Metabolism of triglyceride-rich lipoproteins in health and dyslipidaemia

Accumulating evidence points to the causal role of triglyceride-rich lipoproteins and their cholesterol-enriched remnants in atherogenesis. Genetic studies in particular have not only revealed a relationship between plasma triglyceride levels and the risk of atherosclerotic cardiovascular disease, but have also identified key proteins responsible for the regulation of triglyceride transport. Kinetic studies in humans using stable isotope tracers have been especially useful in delineating the function of these proteins and revealing the hitherto unappreciated complexity of triglyceride-rich lipoprotein metabolism. Given that triglyceride is an essential energy source for mammals, triglyceride transport is regulated by numerous mechanisms that balance availability with the energy demands of the body. Ongoing investigations are focused on determining the consequences of dysregulation as a result of either dietary imprudence or genetic variation that increases the risk of atherosclerosis and pancreatitis. The identification of molecular control mechanisms involved in triglyceride metabolism has laid the groundwork for a 'precision-medicine' approach to therapy. Novel pharmacological agents under development have specific molecular targets within a regulatory framework, and their deployment heralds a new era in lipid-lowering-mediated prevention of disease. In this Review, we outline what is known about the dysregulation of triglyceride transport in human hypertriglyceridaemia.

Case Studies in Pediatric Lipid Disorders and Their Management

CONTEXT

Identification of modifiable risk factors, including genetic and acquired disorders of lipid and lipoprotein metabolism, is increasingly recognized as an opportunity to prevent premature cardiovascular disease (CVD) in at-risk youth. Pediatric endocrinologists are at the forefront of this emerging public health concern and can be instrumental in beginning early interventions to prevent premature CVD-related events during adulthood.

AIM

In this article, we use informative case presentations to provide practical approaches to the management of pediatric dyslipidemia.

CASES

We present 3 scenarios that are commonly encountered in clinical practice: isolated elevation of low-density lipoprotein cholesterol (LDL-C), combined dyslipidemia, and severe hypertriglyceridemia. Treatment with statin is indicated when the LDL-C is ≥190 mg/dL (4.9 mmol/L) in children ≥10 years of age. For LDL-C levels between 130 and 189 mg/dL (3.4-4.89 mmol/L) despite dietary and lifestyle changes, the presence of additional risk factors and comorbid conditions would favor statin therapy. In the case of combined dyslipidemia, the primary treatment target is LDL-C ≤130 mg/dL (3.4 mmol/L) and the secondary target non-high-density lipoprotein cholesterol <145 mg/dL (3.7 mmol/L). If the triglyceride is ≥400 mg/dL (4.5 mmol/L), prescription omega-3 fatty acids and fibrates are considered. In the case of triglyceride >1000 mg/dL (11.3 mmol/L), dietary fat restriction remains the cornerstone of therapy, even though the landscape of medications is changing.

CONCLUSION

Gene variants, acquired conditions, or both are responsible for dyslipidemia during childhood. Extreme elevations of triglycerides can lead to pancreatitis. Early identification and management of dyslipidemia and cardiovascular risk factors is extremely important.

PoLA/CFPiP/PCS/PSLD/PSD/PSH guidelines on diagnosis and therapy of lipid disorders in Poland 2021

In Poland there are still nearly 20 million individuals with hypercholesterolaemia, most of them are unaware of their condition; that is also why only ca. 5% of patients with familial hypercholesterolaemia have been diagnosed; that is why other rare cholesterol metabolism disorders are so rarely diagnosed in Poland. Let us hope that these guidelines, being an effect of work of experts representing 6 main scientific societies, as well as the network of PoLA lipid centers being a part of the EAS lipid centers, certification of lipidologists by PoLA, or the growing number of centers for rare diseases, with a network planned by the Ministry of Health, improvements in coordinated care for patients after myocardial infarction (KOS-Zawał), reimbursement of innovative agents, as well as introduction in Poland of an effective primary prevention program, will make improvement in relation to these unmet needs in diagnostics and treatment of lipid disorders possible.

Rare Treatments for Rare Dyslipidemias: New Perspectives in the Treatment of Homozygous Familial Hypercholesterolemia (HoFH) and Familial Chylomicronemia Syndrome (FCS)

Purpose of Review

This review aims to summarize the most recent published literature concerning lomitapide and volanesorsen that are approved for the use in HoFH and FCS patients, respectively. Moreover, it will briefly revise the published evidence on novel, non-approved treatments that are under evaluation for the management of these rare forms of dyslipidemias

Recent Findings

The definition of rare dyslipidemias identifies a large number of severe disorders of lipid metabolism of genetic origin. Among them were homozygous familial hypercholesterolemia (HoFH) (OMIM #143890) and familial chylomicronemia syndrome (FCS) (OMIM #238600), which are characterized by a markedly impaired cholesterol- and triglyceride-containing lipoproteins metabolism. They are being particularly associated with poor health outcomes and quality of life. Considering the severity of these diseases, common lipid-lowering drugs are often ineffective or do not allow to achieve the recommended lipid targets to prevent the development of complications. Nowadays, several new drugs have been found to effectively treat HoFH and FCS with an acceptable safety profile.

Summary

Treating patients with HoFH and FCS remains very challenging. However, novel treatment options are emerging and might be considered in addition to conventional therapy for managing these diseases. These novel drugs will possibly change the natural history of these two rare and life-threatening diseases.

Beyond the Usual Suspects: Expanding on Mutations and Detection for Familial Hypercholesterolemia

Introduction: Familial hypercholesterolemia (FH) is a highly prevalent condition, predisposing individuals to premature cardiovascular disease and with a genetic basis more complex than initially thought. Advances in molecular technologies have provided novel insights into the role of next-generation-sequencing, the assessment and classification of newly found variants, the complex genotype-phenotype correlation, and the position of FH in the context of other dyslipidaemias.Areas covered: Understanding the scope of genetic determinants of FH has expanded substantially. This article reviews the current literature on the complexity that comes with this incremental knowledge and highlights the added value of genetic testing as an addition to phenotypic diagnosis of FH. Moreover, we discuss the broad genetic basis of FH, with a focus on the three main FH genes, but we also pay attention to polygenic hypercholesterolemia as well as minor and modulator genes involved in FH.Expert opinion: Both the availability and the need for genetic analysis of FH are on the rise as costs of sequencing continue to drop and new therapies require a genetic diagnosis for reimbursement. However, greater use of genetic testing requires more education of healthcare professionals, since molecular technologies will allow for rapid and accurate evaluation of large numbers of detected variants.