Tendon Xanthomas in Familial Hypercholesterolemia Are Associated With Cardiovascular Risk Independently of the Low-Density Lipoprotein Receptor Gene Mutation

What Causes Premature Coronary Artery Disease?

PURPOSE OF REVIEW

This review provides an overview of genetic and non-genetic causes of premature coronary artery disease (pCAD).

RECENT FINDINGS

pCAD refers to coronary artery disease (CAD) occurring before the age of 65 years in women and 55 years in men. Both genetic and non-genetic risk factors may contribute to the onset of pCAD. Recent advances in the genetic epidemiology of pCAD have revealed the importance of both monogenic and polygenic contributions to pCAD. Familial hypercholesterolemia (FH) is the most common monogenic disorder associated with atherosclerotic pCAD. However, clinical overreliance on monogenic genes can result in overlooked genetic causes of pCAD, especially polygenic contributions. Non-genetic factors, notably smoking and drug use, are also important contributors to pCAD. Cigarette smoking has been observed in 25.5% of pCAD patients relative to 12.2% of non-pCAD patients. Finally, myocardial infarction (MI) associated with spontaneous coronary artery dissection (SCAD) may result in similar clinical presentations as atherosclerotic pCAD. Recognizing the genetic and non-genetic causes underlying pCAD is important for appropriate prevention and treatment. Despite recent progress, pCAD remains incompletely understood, highlighting the need for both awareness and research.

Factors associated with the presence of tendon xanthomas in familial hypercholesterolemia

INTRODUCTION AND OBJECTIVES

Tendon xanthomas (TX) are lipid deposits highly specific to familial hypercholesterolemia (FH). However, there is significant variability in their presentation among FH patients, primarily due to largely unknown causes. Lipoprotein(a) is a well-established independent risk factor for atherosclerotic cardiovascular disease in the general population as well as in FH. Given the wide variability of lipoprotein(a) among FH individuals and the likelihood that TX may result from a proatherogenic and proinflammatory condition, the objective of this study was to analyze the size of TX in the Achilles tendons of FH participants and the variables associated with their presence, including lipoprotein(a) concentration.

METHODS

A cross-sectional study was conducted on 377 participants with a molecular diagnosis of heterozygous FH. Achilles tendon maximum thickness (ATMT) was measured using ultrasonography with standardized equipment and procedures. Demographic variables and lipid profiles were collected. A multivariate linear regression model using a log-Gaussian approach was used to predict TX size. Classical cardiovascular risk factors and lipoprotein(a) were included as explanatory variables.

RESULTS

The mean low-density lipoprotein cholesterol level was 277mg/dL without lipid-lowering treatment, and the median ATMT was 5.50mm. We demonstrated that age, sex, low-density lipoprotein cholesterol, and lipoprotein(a) were independently associated with ATMT. However, these 4 variables did not account for most the interindividual variability observed (R2=0.205).

CONCLUSIONS

TX, a characteristic hallmark of FH, exhibit heterogeneity in their presentation. Interindividual variability can partially be explained by age, male sex, low-density lipoprotein cholesterol, and lipoprotein(a) but these factors account for only 20% of this heterogeneity.

Two Cases of Sitosterolemia Falsely Diagnosed as Familial Hypercholesterolemia: Could Digging Deeper Have Avoided Harm?

Sitosterolemia is a rare monogenic lipid disease characterized by the excessive uptake of phytosterols and their accumulation in blood and tissues. Clinically, it can present with hypercholesterolemia and xanthomas, often causing it to be misdiagnosed as familial hypercholesterolemia (FH). The diagnosis of sitosterolemia can easily be confirmed and distinguished from FH with a sterol profile and genetic investigations. Here, we report a sibship of 2 sisters with sitosterolemia initially misdiagnosed as FH. This case report illustrates the importance of considering rare conditions, such as sitosterolemia, as a differential diagnosis in patients with hypercholesterolemia, xanthomas, and hematologic anomalies. It also emphasizes the underdiagnosis of sitosterolemia and the benefits of using sterol profiles and genetic testing in the diagnostic process to initiate the appropriate therapy and avoid harm to patients.

Physical signs and atherosclerotic cardiovascular disease in familial hypercholesterolemia: the HELLAS-FH Registry

AIMS

Three physical signs, namely tendon xanthomas, corneal arcus and xanthelasma, have been associated with heterozygous familial hypercholesterolemia (heFH). The prevalence and clinical significance of these signs are not well established among contemporary heFH individuals. This study explored the frequency as well as the association of these physical signs with prevalent atherosclerotic cardiovascular disease (ASCVD) in heFH individuals.

METHODS

Data from the Hellenic Familial Hypercholesterolemia Registry were applied for this analysis. The diagnosis of heFH was based on the Dutch Lipid Clinic Network Score. Multivariate logistic regression analysis was conducted to examine the association of heFH-related physical signs with prevalent ASCVD.

RESULTS

Adult patients ( n  = 2156, mean age 50 ± 15 years, 47.7% women) were included in this analysis. Among them, 14.5% had at least one heFH-related physical sign present. The prevalence of corneal arcus before the age of 45 years was 6.6%, tendon xanthomas 5.3%, and xanthelasmas 5.8%. Among physical signs, only the presence of corneal arcus before the age of 45 years was independently associated with the presence of premature coronary artery disease (CAD). No association of any physical sign with total CAD, stroke or peripheral artery disease was found. Patients with physical signs were more likely to receive higher intensity statin therapy and dual lipid-lowering therapy, but only a minority reached optimal lipid targets.

CONCLUSION

The prevalence of physical signs is relatively low in contemporary heFH patients. The presence of corneal arcus before the age of 45 years is independently associated with premature CAD.

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.

The 20-Year Diagnostic Odyssey of a Milder Form of Cerebrotendinous Xanthomatosis

Tendinous xanthomas are usually a sign of genetic dyslipidemias and are said to be pathognomonic for familial hypercholesterolemia. However, the differential diagnosis must also include rarer forms of genetic dyslipidemias such as cerebrotendinous xanthomatosis (CTX). In this report, we present the diagnostic odyssey of a French-Canadian patient presenting with Achilles tendon xanthomas and an unusual mild to moderate hypercholesterolemia. Comprehensive biochemical and genetic investigations confirmed the diagnosis of CTX, 20 years after the onset of her first symptoms. We also describe a new variant in the CYP27A1 gene associated with this atypical case and expand the clinical phenotype of this rare genetic condition. CTX is thought to be underdiagnosed, and early diagnosis and treatment of this disease is essential as it has been shown to greatly improve the patient's symptoms and prognosis.

The risk of various types of cardiovascular diseases in mutation positive familial hypercholesterolemia; a review

Familial hypercholesterolemia (FH) is a common, inherited disease characterized by high levels of low-density lipoprotein Cholesterol (LDL-C) from birth. Any diseases associated with increased LDL-C levels including atherosclerotic cardiovascular diseases (ASCVDs) would be expected to be overrepresented among FH patients. There are several clinical scoring systems aiming to diagnose FH, however; most individuals who meet the clinical criteria for a FH diagnosis do not have a mutation causing FH. In this review, we aim to summarize the literature on the risk for the various forms of ASCVD in subjects with a proven FH-mutation (FH+). We searched for studies on FH+ and cardiovascular diseases and also included our and other groups published papers on FH + on a wide range of cardiovascular and other diseases of the heart and vessels. FH + patients are at a markedly increased risk of a broad range of ASCVD. Acute myocardial infarction (AMI) is the most common in absolute numbers, but also aortic valve stenosis is by far associated with the highest excess risk. Per thousand patients, we observed 3.6 incident AMI per year compared to 1.9 incident aortic valve stenosis, however, standardized incidence ratio (SIR) for incident AMI was 2.3 compared to 7.9 for incident aortic valve stenosis. Further, occurrence of ischemic stroke seems not to be associated with increased risk in FH+. Clinicians should be aware of the excess risk of almost all kind of ASCVD in FH+, and the neutral risk of stroke need to be studied further in FH + patients.

Current causes of death in familial hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia (FH) is a codominant autosomal disease characterized by high low-density lipoprotein cholesterol (LDLc) and a high risk of premature cardiovascular disease (CVD). The molecular bases have been well defined, and effective lipid lowering is possible. This analysis aimed to study the current major causes of death of genetically defined heterozygous familial hypercholesterolemia (heFH).

METHODS

A case‒control study was designed to analyse life-long mortality in a group of heFH and control families. Data from first-degree family members of cases and controls (nonconsanguineous cohabitants), including deceased relatives, were collected from a questionnaire and review of medical records. Mortality was compared among heFH patients, nonheFH patients, and nonconsanguineous family members.

RESULTS

A total of 813 family members were analysed, 26.4% of whom were deceased. Among the deceased, the mean age of death was 69.3 years in heFH individuals, 73.5 years in nonheFH individuals, and 73.2 years in nonconsanguineous individuals, without significant differences. CVD was the cause of death in 59.7% of heFH individuals, 37.7% of nonheFH individuals, and 37.4% of nonconsanguineous individuals (P = 0.012). These differences were greater after restricting the analyses to parents. The hazard ratio of dying from CVD was 2.85 times higher (95% CI, (1.73-4.69) in heFH individuals than in individuals in the other two groups (non-FH and nonconsanguineous), who did not differ in their risk.

CONCLUSIONS

CVD mortality in heFH individuals is lower and occurs later than that described in the last century but is still higher than that in non-FH individuals. This improved prognosis of CVD risk is not associated with changes in non-CVD mortality.

HDL Cholesterol Efflux and Serum Cholesterol Loading Capacity Alterations Associate to Macrophage Cholesterol Accumulation in FH Patients with Achilles Tendon Xanthoma

Achilles tendon xanthoma (ATX) formation involves macrophage cholesterol accumulation within the tendon, similar to that occurring in atheroma. Macrophage cholesterol homeostasis depends on serum lipoprotein functions, namely the high-density lipoprotein (HDL) capacity to promote cell cholesterol efflux (cholesterol efflux capacity, CEC) and the serum cholesterol loading capacity (CLC). We explored the HDL-CEC and serum CLC, comparing 16 FH patients with ATX to 29 FH patients without ATX. HDL-CEC through the main efflux mechanisms mediated by the transporters ATP binding cassette G1 (ABCG1) and A1 (ABCA1) and the aqueous diffusion (AD) process was determined by a cell-based radioisotopic technique and serum CLC fluorimetrically. Between the two groups, no significant differences were found in terms of plasma lipid profile. A trend toward reduction of cholesterol efflux via AD and a significant increase in ABCA1-mediated HDL-CEC (+18.6%) was observed in ATX compared to no ATX patients. In ATX-presenting patients, ABCG1-mediated HDL-CEC was lower (−11%) and serum CLC was higher (+14%) compared to patients without ATX. Considering all the patients together, ABCG1 HDL-CEC and serum CLC correlated with ATX thickness inversely (p = 0.013) and directly (p < 0.0001), respectively. In conclusion, lipoprotein dysfunctions seem to be involved in ATX physiopathology and progression in FH patients.

Relations of physical signs to genotype, lipid and inflammatory markers, coronary stenosis or calcification, and outcomes in patients with heterozygous familial hypercholesterolemia

BACKGROUND

Although the presence of physical signs [tendon xanthomas and/or corneal arcus (TX/CA)], are associated with the risk of coronary artery disease in patients with heterozygous familial hypercholesterolemia (HeFH), their relationship with genotypes and clinical characteristics has not been fully determined. This study aimed to examine the association of TX/CA with genetic mutation, lipid- and inflammation-related markers, the severity of coronary stenosis or calcification, and cardiovascular events (CVEs) in patients with HeFH.

METHODS

LDLR, APOB, and PCSK9 genes were screened in 523 HeFH patients, and patients with TX/CA (n = 50) were 1:4 propensity score-matched to patients without TX/CA (n = 200) to adjust for age and sex. Laboratory markers (proprotein convertase subtilisin/kexin type 9 [PCSK9], lipoprotein(a) and high-sensitivity C-reactive protein [hsCRP]), computed tomography angiography, coronary angiography, and follow-up for CVEs were performed.

RESULTS

Patients with physical signs had significantly higher low-density lipoprotein cholesterol levels; higher PCSK9 or hsCRP concentrations; more LDLR positive mutations; and higher prevalence of high tertiles of Gensini, SYNTAX and Jeopardy scores as well as coronary artery calcium scores than did those without. Over an average follow-up of 3.7 years, the incidence of CVEs was significantly higher in patients with TX/CA (log-rank p < 0.001). Patients with physical signs and mutation positivity had threefold higher risks of CVEs (adjusted hazard ratio 3.34, 95% confidence interval 1.04-10.72, p = 0.024).

CONCLUSIONS

Physical signs were associated with genotypes and phenotypes, and worse outcomes in patients with HeFH, suggesting that these signs may help in risk stratification in these patients.

Achilles tendon thickness is associated with coronary lesion severity in acute coronary syndrome patients without familial hypercholesterolemia

BACKGROUND

Thickening of Achilles tendon (≥9 mm on radiography) is one of the diagnostic criteria for familial hypercholesterolemia (FH). Since FH is associated with premature coronary artery disease (CAD) including acute coronary syndrome (ACS), measurement of Achilles tendon thickness (ATT) is important for early diagnosis of FH. However, clinical significance of mild thickening of Achilles tendon in non-FH patients with CAD is unclear. The present study investigated the association of ATT with coronary lesion severity in early-onset ACS without clinically diagnosed FH.

METHODS

From outpatients who had a history of ACS under 60 years old, 76 clinically non-FH subjects (71 men and 5 women; mean age at the onset of ACS, 50.5 years) with maximum ATT of <9 mm were enrolled in this study. The severity of coronary lesions was assessed by SYNTAX score derived from coronary angiography at the onset of ACS.

RESULTS

ATT levels were not significantly different among patients with ST-elevation myocardial infarction (STEMI, n=47), non-STEMI (n=12), and unstable angina (n=17). Whereas, both average and maximum ATT were significantly larger in patients with multivessel lesions (n=25) than in those with single-vessel disease (n=51). Furthermore, SYNTAX score was positively correlated with average ATT (r=0.368, p=0.0011) and maximum ATT (r=0.388, p=0.0005). As for the relation to clinical parameters, maximum ATT had positive correlations with body mass index and C-reactive protein. A multiple regression analysis revealed that average and maximum ATT were significantly associated with SYNTAX score, independently of various confounding factors.

CONCLUSIONS

Our findings demonstrated that ATT, even though its level was <9 mm, was associated with coronary lesion severity in clinically non-FH patients with early-onset ACS. Apart from diagnosing FH, ATT may be a predictor of the progression of CAD.

Familial Hypercholesterolemia: Do HDL Play a Role?

Cardiovascular disease (CVD) in heterozygous familial hypercholesterolemia (HeFH), the most frequent monogenic disorder of human metabolism, is largely driven by low-density lipoprotein (LDL) cholesterol concentrations. Since the CVD rate differs considerably in this population, beyond the lifetime LDL cholesterol vascular accumulation, other classical risk factors are involved in the high cardiovascular risk of HeFH. Among other lipoprotein disturbances, alterations in the phenotype and functionality of high-density lipoproteins (HDL) have been described in HeFH patients, contributing to the presence and severity of CVD. In fact, HDL are the first defensive barrier against the burden of high LDL cholesterol levels owing to their contribution to reverse cholesterol transport as well as their antioxidant and anti-inflammatory properties, among others. In this context, the present narrative review aimed to focus on quantitative and qualitative abnormalities in HDL particles in HeFH, encompassing metabolic, genetic and epigenetic aspects.

Cutaneous manifestations in familial hypercholesterolaemia

BACKGROUND AND AIMS

Familial hypercholesterolaemia (FH) is associated with high cardiovascular risk and underdiagnosed. Cutaneous manifestations are traditionally used as a major criterion of FH. They are included in the Dutch Lipid Clinic Network or Simon Broome registry criteria. The objective of this study was to evaluate cutaneous manifestations in contemporary FH patients.

METHODS

We prospectively analysed the clinical presentation of FH patients referred to a University lipid clinic and validated these data in the German FH registry CaRe High.

RESULTS

Physical examination revealed that only 14.4% of the FH patients in the lipid clinic cohort (n = 223) showed cutaneous manifestations. An arcus cornealis was present in 0.9%, xanthomata in 1.8%, and xanthelasmata in 12.1%. Xanthelasmata are not part of the clinical scores, but represented 84.4% of all cutaneous manifestations. In 42.6% (n = 95) of the patients, genetic analysis was available. A causal FH mutation was detected in 50.5%. Among carriers, 66.7% had no cutaneous manifestation, 8.3% exhibited an arcus cornealis or xanthomata, and 25.0% had xanthelasmata. In the CaRe High FH registry, data on cutaneous manifestations were available in n = 1274 patients. 3.5% had xanthomata, 5.7% an arcus cornealis, and 7.7% at least one of both; xanthelasmata were present in 10.3%.

CONCLUSIONS

Cutaneous manifestations are only present in a minority of contemporary patients with FH including the subgroup with monogenic FH mutations. Although rare, the cutaneous signs have value in terms of specificity. However, the clinical characteristics shared by the majority of FH patients may be better suited for screening purposes.

Familial hypercholesterolemia in Mexico: Initial insights from the national registry

BACKGROUND

Familial hypercholesterolemia (FH) remains underdiagnosed and undertreated.

OBJECTIVE

Report the results of the first years (2017-2019) of the Mexican FH registry.

METHODS

There are 60 investigators, representing 28 federal states, participating in the registry. The variables included are in accordance with the European Atherosclerosis Society (EAS) FH recommendations.

RESULTS

To date, 709 patients have been registered, only 336 patients with complete data fields are presented. The mean age is 50 (36-62) years and the average time since diagnosis is 4 (IQR: 2-16) years. Genetic testing is recorded in 26.9%. Tendon xanthomas are present in 43.2%. The prevalence of type 2 diabetes is 11.3% and that of premature CAD is 9.8%. Index cases, male gender, hypertension and smoking were associated with premature CAD. The median lipoprotein (a) level is 30.5 (IQR 10.8-80.7) mg/dl. Statins and co-administration with ezetimibe were recorded in 88.1% and 35.7% respectively. A combined treatment target (50% reduction in LDL-C and an LDL-C <100 mg/dl) was achieved by 13.7%. Associated factors were index case (OR 3.6, 95%CI 1.69-8.73, P = .002), combination therapy (OR 2.4, 95%CI 1.23-4.90, P = .011), type 2 diabetes (OR 2.8, 95%CI 1.03-7.59, P = .036) and age (OR 1.023, 95%CI 1.01-1.05, P = .033).

CONCLUSION

The results confirm late diagnosis, a lower than expected prevalence and risk of ASCVD, a higher than expected prevalence of type 2 diabetes and undertreatment, with relatively few patients reaching goals. Recommendations include, the use of combination lipid lowering therapy, control of comorbid conditions and more frequent genetic testing in the future.

Genetics of Hypercholesterolemia: Comparison Between Familial Hypercholesterolemia and Hypercholesterolemia Nonrelated to LDL Receptor

Severe hypercholesterolemia (HC) is defined as an elevation of total cholesterol (TC) due to the increase in LDL cholesterol (LDL-C) >95th percentile or 190 mg/dl. The high values of LDL-C, especially when it is maintained over time, is considered a risk factor for the development of atherosclerotic cardiovascular disease (ASCVD), mostly expressed as ischemic heart disease (IHD). One of the best characterized forms of severe HC, familial hypercholesterolemia (FH), is caused by the presence of a major variant in one gene (LDLR, APOB, PCSK9, or ApoE), with an autosomal codominant pattern of inheritance, causing an extreme elevation of LDL-C and early IHD. Nevertheless, an important proportion of serious HC cases, denominated polygenic hypercholesterolemia (PH), may be attributed to the small additive effect of a number of single nucleotide variants (SNVs), located along the whole genome. The diagnosis, prevalence, and cardiovascular risk associated with PH has not been fully established at the moment. Cascade screening to detect a specific genetic defect is advised in all first- and second-degree relatives of subjects with FH. Conversely, in the rest of cases of HC, it is only advised to screen high values of LDL-C in first-degree relatives since there is not a consensus for the genetic diagnosis of PH. FH is associated with the highest cardiovascular risk, followed by PH and other forms of HC. Early detection and initiation of high-intensity lipid-lowering treatment is proposed in all subjects with severe HC for the primary prevention of ASCVD, with an objective of LDL-C <100 mg/dl or a decrease of at least 50%. A more aggressive reduction in LDL-C is necessary in HC subjects who associate personal history of ASCVD or other cardiovascular risk factors.

The value of physical signs in identifying patients with familial hypercholesterolemia in the era of genetic testing

Familial hypercholesterolemia (FH) is a common, inherited disorder of cholesterol metabolism characterized by very high plasma concentrations of low-density lipoprotein cholesterol. It is crucial to diagnose and treat this disorder early since if left untreated it increases the risk for coronary artery disease (CAD) at least by 10-fold. Although genetic testing for FH, when available and affordable, should ideally be offered to most individuals with clinical phenotype suggestive of FH, it is underutilized in most countries. Therefore, FH diagnosis in the majority of cases is made by combining cholesterol levels and clinical characteristics of the patient leaving the need for genetic testing usually in equivocal cases. The presence of some cutaneous and ocular signs can raise the suspicion or even lead to the diagnosis of FH among usually "healthy" individuals. These physical signs comprise cutaneous lesions such as tendon xanthomas or the less specific xanthelasmata and ocular signs, such as corneal arcus in individuals under the age of 45 years. The presence of these signs should prompt the physician to request lipid tests and use clinical scores to diagnose FH. If the diagnosis of FH is likely, aggressive lipid-lowering therapy should be initiated to reduce the risk of CAD and a cascade screening of family members should also be requested.

State-of-the-Art Pediatric Coronary Artery Bypass Surgery: a Literature Review

Objective

To examine the results of various myocardial revascularization techniques in pediatric patients to better understand the strategies for surgical treatment of coronary artery pathologies.

Methods

We analyzed 61 publications dedicated to the indications, methods, and results of coronary bypass surgery in children. Due to the small size of this cohort, case reports are also included in our review.

Results

The main indications for coronary bypass grafting in children are Kawasaki disease, myocardial revascularization as a necessary procedure during the congenital cardiac surgery, to manage intraoperative iatrogenic damage to coronary arteries, and homozygous familial hypercholesterolemia. The use of internal thoracic arteries as conduits for coronary bypass grafting in children with Kawasaki disease showed significantly better results in long-term functionality compared to autovenous conduits (87% and 44%, respectively, P<0.001). Acute and late coronary events after arterial switch operation for the transposition of the great arteries, anomalous origin of the left coronary artery from the pulmonary artery, and left main coronary artery atresia are the main congenital heart diseases where surgical correction involves interventions on the coronary arteries.

Conclusion

The internal thoracic artery is a reliable and durable conduit that demonstrates proven growth potential in children.

An age-matched computed tomography angiographic study of coronary atherosclerotic plaques in patients with familial hypercholesterolaemia

BACKGROUND AND AIMS

Familial hypercholesterolaemia (FH) is characterised by a high, but variable risk of premature coronary artery disease (CAD). Cardiac computed tomography angiography (CCTA) can be employed to assess subclinical coronary atherosclerosis. We investigated the features and distribution of coronary artery plaques in asymptomatic patients with and without genetically confirmed heterozygous FH.

METHODS

We undertook an aged-matched case-control study of asymptomatic phenotypic FH patients with (cases, M+) and without (controls, M-) an FH-causing mutation. Coronary atherosclerosis was assessed by CCTA and calcium scoring. Coronary segments were evaluated for global and vessel-level coronary plaques and degree of stenosis.

RESULTS

We studied 104 cases and 104 controls (mean age 49.9 ± 10.4 years), who had a similar spectrum of non-cardiovascular risk factors. Pre-treatment plasma LDL-cholesterol was higher in the M+ than M- group (7.8 ± 2.1 vs 6.2 ± 1.2 mmol/L, p<0.001). There was a greater proportion of patients with mixed and calcified plaque, as well as a higher coronary artery calcium score and segment stenosis score (all p<0.05), in the M+ compared with the M- group. M+ patients also had a significantly higher frequency of coronary artery calcium in the left main and anterior descending and right coronary arteries (all p<0.05), but not in the left circumflex.

CONCLUSIONS

Among patients with phenotypic FH, those with a genetically confirmed diagnosis had a higher frequency and severity of coronary atherosclerotic plaques, and specifically more advanced calcified plaques.

Clinical and genetic differences between heterozygous familial hypercholesterolemia patients with and without type 2 diabetes

INTRODUCTION AND OBJECTIVES

The lower prevalence of type 2 diabetes mellitus (T2DM) in patients with heterozygous familial hypercholesterolemia (HeFH) could explain why T2DM has not always been identified as an independent predictor of cardiovascular disease (CVD) in different familial hypercholesterolemia cohort studies. The aim of the present study was to evaluate clinical and genetic aspects of HeFH patients with T2DM in the dyslipidemia registry of the Spanish Arteriosclerosis Society.

METHODS

HeFH patients were classified according to the presence or absence of T2DM. The clinical, biochemical and genetic characteristics of the 2 groups were compared.

RESULTS

Of the 2301 patients with primary hypercholesterolemia included in the registry, 1724 with a probable or definite diagnosis according to the Dutch Lipid Clinic Network score were finally included. HeFH patients with T2DM had a higher rate of CVD and a less favorable lipid profile, with higher total cholesterol (366.9±86.7mg/dL vs 342.0±74.7mg/dL; mean difference 24.894; 95%CI, 5.840-43.949) and non-high-density lipoprotein cholesterol (316.9±87.8mg/dL vs 286.4±75.4mg/dL; mean difference 30.500; 95%CI, 11.211-49.790) levels. No significant differences were found between the groups concerning the specific type of HeFH-causing mutation (P=.720). After adjustment for major risk factors, logistic regression analysis confirmed a relationship between T2DM and the presence of CVD (OR, 2.01; 95%CI, 1.18-3.43; P=.010).

CONCLUSIONS

HeFH patients with T2DM have a higher rate of CVD and a less favorable lipid profile, regardless of genetic mutation type. In these patients, T2DM is associated with the presence of CVD.

Prognostic value of exercise tolerance test for predicting cardiovascular disease in asymptomatic individuals with heterozygous familiar hypercholesterolemia

Heterozygous familiar hypercholesterolemia (hFH) is an autosomal dominant inherited dyslipidemia, associated with premature cardiovascular disease (CVD). Aim of the study was to define prognostic factors for cardiovascular events (CVE) in asymptomatic individuals with hFH. All participants with recent diagnosis of hFH were recruited from the outpatient lipid clinic from 1987 to 2016, without any previous clinical evidence of CVD. A detailed clinical evaluation and laboratory investigation was obtained. Exercise tolerance test (ETT) was performed until maximum exercise capacity was achieved, without evidence of ischemia. Primary endpoint of the study was the first CVE. Four hundred fifty one participants were followed up for 10 ± 8 years, with 68 recorded cases of CVD (15%). Cumulative incidence of CVD was 15%, 24% and 32% for the 3 decades, respectively. In univariate analysis, male gender (p = 0.016), progression of age (p < 0.001), menopause (p = 0.030), waist-hip ratio (p = 0.043) and increased levels of Lp(α) (p = 0.014) were significantly associated with increased CVD incidence; whereas, exercise capacity (p = 0.025), low variation of heart rate (HR) during all stages of ETT compared to resting state (p = 0.020), maximum systolic (p = 0.014) and diastolic (p < 0.001) blood pressure were inversely associated with CVD. In multi-adjusted analysis, male gender (p < 0.001), duration of ETT (p = 0.023), estimated HR (p = 0.029), variation of HR during ETT compared to resting state (p < 0.05) and maximum diastolic pressure (p = 0.044) were significantly associated with CVD. Parameters of ETT in asymptomatic individuals with hFH, without any evidence of ischemia, may predict CVD in these high-risk patients after decades of observation.

Is the coronary artery calcium score the first-line tool for investigating patients with severe hypercholesterolemia?

Background

Coronary artery calcium (CAC) is known as a reliable tool for estimating risk of myocardial infarction, coronary death, all-cause mortality and is even used to evaluate suitable asymptomatic patients. We therefore aimed to evaluate whether CAC scoring can be applied in the algorithm for clinical examination of patients with severe hypercholesterolemia (SH).

Methods

During the period of 2016–2017 a total of 213 asymptomatic adults, underwent computed tomography angiography to evaluate their CAC scoring. The sample consisted of 110 patients with SH and 103 age and sex matched controls without dyslipidemia and established cardiovascular disease.

Results

In total there were 79 (37.2%) subjects with elevated (≥25th) CAC percentiles. Out of them 47 (59.5%) had SH and 32 (40.5%) did not. CAC score did not differ between groups (SH (+) 140.30 ± 185.72 vs SH (−) 87.84 ± 140.65, p = 0.146), however there was a comparable difference in how the participants of these groups distributed among different percentile groups (p = 0.044). Gender, blood pressure, tabaco use, physical activity, family history of coronary artery disease and diabetes mellitus were not associated with CAC score (p > 0.05). There were no significant correlations between biochemical parameters and CAC percentiles except for increase in lipoprotein(a) (p = 0.038). Achilles tendon pathology, visceral obesity, body mass index and increased waist-hip ratio were not associated with CAC percentiles either (p > 0.05).

Conclusions

CAC score is not associated with presence of SH. CAC score is not an appropriate diagnostic tool in the algorithm for clinical examination of patients with SH. Further larger studies are needed to support our findings.

Achilles tendon ultrasonography - A useful screening tool for cardiovascular risk estimation in patients with severe hypercholesterolemia

BACKGROUND AND AIMS

Achilles tendon lesions have long been associated with genetic defects in lipid metabolism and increased risk of cardiovascular diseases (CVD). With this study we aimed to evaluate the usefulness of Achilles tendon ultrasonography in identifying people at greater risk among subjects with severe hypercholesterolemia (SH) in a high-risk population.

METHODS

During the period of 2016-2017 a total of 213 participants were enrolled in this case-control study. Data of 110 patients with SH and 103 age and sex matched controls without dyslipidaeplemia and established CVD was collected.

RESULTS

Achilles tendinopathy (AT) was present in 42.7% of subjects with SH and in 29.1% of controls (p = 0.039). Stronger association between SH and AT was seen in women - 24.1% vs 2.0% (p = 0.001). SH increased odds of AT by 1.815 (95% CI, 1.028-3.206). Prevalence of AT was higher in males despite presence (SH⁺) or absence (SH^-) of severe hypercholesterolemia (SH⁺ 60.7% vs 24.1%, SH^- 55.8% vs 2.0%, p < 0.001). AT was associated with higher proportion of subjects exceeding normal mean values of TC (80.5% vs 52.9%, p = 0.001), LDL-C (76.6% vs 52.2%), TG (54.5% vs. 22.1%), ApoB (57.1% vs 22.2%), ApoE (44.0% vs 22.4%) levels and ApoB/ApoA ratio (46.1% vs 21.5%) (p = 0.001) and family history of premature coronary heart disease (CHD).

CONCLUSIONS

AT is more prevalent among subjects with SH and is associated with higher levels of TC, TG, LDL-C, ApoB, ApoE, ApoB/ApoA ratio, family history of premature CHD. SH increases the odds of developing AT.

Prevalence of heterozygous familial hypercholesterolemia and combined hyperlipidemia phenotype in very young survivors of myocardial infarction and their association with the severity of atheromatous burden

BACKGROUND

Heterozygous familial hypercholesterolemia (HeFH) and combined hyperlipidemia (CHL) phenotype are associated with premature myocardial infarction (MI).

OBJECTIVE

To assess the prevalence of HeFH and CHL phenotype among young survivors of MI and compare patients' characteristics with these 2 lipid disorders.

METHODS

We recruited 382 young survivors of MI (≤40 years). Fasting lipids, lipoprotein(a) [Lp(a)], apolipoprotein A-1, and apolipoprotein B (apoB) levels were determined. Using the Dutch Lipid Clinic Network (DLCN) algorithm, patients having definite or probable HeFH were identified. Patients with apoB levels >120 mg/dL and triglyceride levels >170 mg/dL (1.92 mmol/L) [>90th percentile of 326 age and sex-matched healthy controls] were classified as having CHL phenotype. Common carotid artery intima-media thickness (CCA-IMT) was measured by B-mode ultrasonography.

RESULTS

Eighty-one patients (21.2%) had definite/probable HeFH and 62 (16.2%) had CHL phenotype. Twenty-three patients fulfilled the criteria for both HeFH and CHL phenotype and were removed from further comparisons. Patients with HeFH (n = 58) had higher levels of total cholesterol, low-density lipoprotein (LDL)-cholesterol, Lp(a), and apoB, whereas patients with CHL phenotype (n = 39) had higher levels of triglycerides and lower high-density lipoprotein (HDL)-cholesterol levels. The prevalence of metabolic syndrome was higher in patients with CHL phenotype compared to those with HeFH (67.0% vs 16.4%, P < .001). Patients with HeFH had more extensive coronary artery disease (3-vessel disease: 36.2% vs 12.8%, P = .011) and greater right CCA-IMT (0.67 ± 0.11 mm vs 0.56 ± 0.09 mm, P < .001) and left CCA-IMT (0.68 ± 0.10 mm vs 0.56 ± 0.08 mm, P < .001) compared to CHL phenotype patients.

CONCLUSIONS

Both HeFH and CHL phenotype are common among patients with premature MI. CHL phenotype compared to HeFH is associated with less atheromatous burden in coronary and carotid arteries at the time of first MI.

Association of Achilles tendon thickness and LDL-cholesterol levels in patients with hypercholesterolemia

Background

Achilles tendons are the most common sites of tendon xanthomas that are commonly caused by disturbance of lipid metabolism. Achilles tendon thickening is the early characteristic of Achilles tendon xanthomas. The relationship between Achilles tendon thickness (ATT) and LDL-C levels, and risk factors of ATT in patients with hypercholesterolemia, have thus far been poorly documented.

Methods

A total of 205 individuals, aged 18-75 years, were enrolled from March 2014 to March 2015. According to the LDL-C levels and the “Chinese Guidelines on Prevention and Treatment of Dyslipidemia in Adults”, all subjects were divided into 3 groups: normal group (LDL-C < 3.37 mmol/L, n = 51); borderline LDL-C group (3.37 mmol/L ≤ LDL-C ≤ 4.12 mmol/L, n = 50); and hypercholesterolemia group (LDL ≥ 4.14 mmol/L, n = 104). ATT was measured using a standardized digital radiography method and the results were compared among the 3 groups. The correlation between ATT and serum LDL-C levels was analyzed by Pearson’s correlation, and the risk factors of ATT were determined by the logistic regression model.

Results

ATT in borderline LDL-C group was 8.24 ± 1.73 mm, markedly higher than 6.05 ± 0.28 mm of normal group (P < 0.05). ATT in hypercholesterolemia group was 9.42 ± 3.63 mm which was significantly higher than that of normal group (P < 0.005) and that of borderline LDL-C group (P < 0.05). There was a positive correlation between the serum LDL-C levels and ATT (r = 0.346, P < 0.001). The serum LDL-C level was a risk factor (OR = 1.871, 95% CI: 1.067-3.280) while the levels of HDL-C (OR = 0.099, 95% CI: 0.017-0.573) and Apo AI (OR = 0.035, 95% CI: 0.003-0.412) were protective factors of ATT.

Conclusions

ATT might serve as a valuable auxiliary diagnostic index for hypercholesterolemia and used for the assessment and management of cardiovascular disease.

Spectrum of low-density lipoprotein receptor (LDLR) mutations in a cohort of Sri Lankan patients with familial hypercholesterolemia - a preliminary report

BACKGROUND

Hypercholesterolemia is a major determinant of cardiovascular disease-associated morbidity and mortality. Mutations in the LDL-receptor (LDLR) gene are implicated in the majority of the cases with familial hypercholesterolemia (FH). However, the spectrum of mutations in the LDLR gene in Sri Lankan patients has not been investigated. The objective of this study was to report the frequency and spectrum of variants in LDLR in a cohort of Sri Lankan patients with FH.

METHODS

A series of consecutive patients with FH, diagnosed according to Modified Simon Broome criteria or Dutch Lipid Clinic Network criteria at the University Medical Unit, Colombo, were recruited. Clinical data was recorded. DNA was extracted from peripheral blood samples. The LDLR gene was screened for genetic variants by Sanger sequencing.

RESULTS

A total of 27 patients [13 (48%) males, 14 (52%) females; age range 24-73 years] were tested. Clinical features found among these 27 patients were: xanthelasma in 5 (18.5%), corneal arcus in 1 (3.7%), coronary artery disease (CAD) in 10 (37%), and a family history of hypercholesterolemia and/or CAD in 24 (88.9%) patients. In the entire cohort, mean total cholesterol was 356.8 mg/dl (±66.4) and mean LDL-cholesterol was 250.3 mg/dl (±67.7). Sanger sequencing of the 27 patients resulted in the identification of known pathogenic missense mutations in 5 (18.5%) patients. Four were heterozygotes for 1 mutation each. They were c.682G > C in 2 patients, c.1720C > A in 1 patient, and c.1855 T > A in 1 patient. One patient with severe FH phenotypes was a compound heterozygote for one known mutation, c.2289G > T, and another missense variant, c.1670C > G (p.Thr557Ser), with unknown functional impact. This latter variant has not been reported in any other population previously.

CONCLUSIONS

The frequency of known mutations in the LDLR gene in this cohort of patients was markedly low compared to frequencies reported in other populations. This highlights the likelihood of a complex, polygenic inheritance of FH in Sri Lankan patients, indicating the need for a comprehensive genetic evaluation that includes the screening for mutations in other genes that cause FH, such as APOB, PCSK9, and LDLRAP1.

Association between non-cholesterol sterol concentrations and Achilles tendon thickness in patients with genetic familial hypercholesterolemia

Background

Familial hypercholesterolemia (FH) is a genetic disorder that result in abnormally high low-density lipoprotein cholesterol levels, markedly increased risk of coronary heart disease (CHD) and tendon xanthomas (TX). However, the clinical expression is highly variable. TX are present in other metabolic diseases that associate increased sterol concentration. If non-cholesterol sterols are involved in the development of TX in FH has not been analyzed.

Methods

Clinical and biochemical characteristics, non-cholesterol sterols concentrations and Aquilles tendon thickness were determined in subjects with genetic FH with (n = 63) and without (n = 40) TX. Student-t test o Mann–Whitney test were used accordingly. Categorical variables were compared using a Chi square test. ANOVA and Kruskal–Wallis tests were performed to multiple independent variables comparison. Post hoc adjusted comparisons were performed with Bonferroni correction when applicable. Correlations of parameters in selected groups were calculated applying the non-parametric Spearman correlation procedure. To identify variables associated with Achilles tendon thickness changes, multiple linear regression were applied.

Results

Patients with TX presented higher concentrations of non-cholesterol sterols in plasma than patients without xanthomas (P = 0.006 and 0.034, respectively). Furthermore, there was a significant association between 5α-cholestanol, β-sitosterol, desmosterol, 24S-hydroxycholesterol and 27-hydroxycholesterol concentrations and Achilles tendon thickness (p = 0.002, 0.012, 0.020, 0.045 and 0.040, respectively).

Conclusions

Our results indicate that non-cholesterol sterol concentrations are associated with the presence of TX. Since cholesterol and non-cholesterol sterols are present in the same lipoproteins, further studies would be needed to elucidate their potential role in the development of TX.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1380-3) contains supplementary material, which is available to authorized users.

Familial Hypercholesterolaemia Diagnosis and Management

Familial hypercholesterolaemia is the most common monogenic disorder associated with premature coronary artery disease. Mutations are most frequently found in the LDL receptor gene. Clinical criteria can be used to make the diagnosis; however, genetic testing will confirm the disorder and is very useful for cascade screening. Early identification and adequate treatment can improve prognosis, reducing negative clinical cardiovascular outcomes. Patients with familial hypercholesterolaemia are considered at high cardiovascular risk and the treatment target is LDL cholesterol <2.6 mmol/l or at least a 50 % reduction in LDL cholesterol. Patients require intensive treatment with statins and ezetimibe and/or colesevelam. Recently, proprotein convertase subtilisin/kexin type 9 inhibitors have been approved for the management of familial hypercholesterolaemia on top of statins.

Spectrum of mutations in index patients with familial hypercholesterolemia in Singapore: Single center study

BACKGROUND AND AIMS

Familial hypercholesterolemia (FH) is an autosomal dominant genetic disease characterized by the presence of high plasma low density lipoproteins cholesterol (LDL-c). Patients with FH, with mutation detected, are at increased risk of premature cardiovascular disease compared to those without mutations. The aim of the study was to assess the type of mutations in patients, clinically diagnosed with FH in Singapore.

METHODS

Patients (probands) with untreated/highest on-treatment LDL-c>4.9 mmol/l were recruited (June 2015 to April 2017). Anthropometric, biochemical indices, blood and family history were collected. DNA was extracted and Next Generation Sequencing (NGS) was performed in 26 lipid-related genes, including LDLR, APOB and PCSK9, and validated using Sanger. Multiplex-ligation probe analyses for LDLR were performed to identify large mutation derangements. Based on HGVS nomenclature, LDLR mutations were classified as "Null"(nonsense, frameshift, large rearrangements) and "Defective"(point mutations which are pathogenic).

RESULTS

Ninety-six probands were recruited: mean age: (33.5 ± 13.6) years. 52.1% (n = 50) of patients had LDLR mutations, with 15 novel mutations, and 4.2% (n = 4) had APOB mutations. Total cholesterol (TC) and LDL-c were significantly higher in those with LDLR mutations compared to APOB and no mutations [(8.53 ± 1.52) vs. (6.93 ± 0.47) vs. (7.80 ± 1.32)] mmol/l, p = 0.012 and [(6.74 ± 0.35) vs. (5.29 ± 0.76) vs. (5.98 ± 1.23)] mmol/l, p=0.005, respectively. Patients with "null LDLR" mutations (n = 13) had higher TC and LDL-c than "defective LDLR" mutations (n = 35): [(9.21 ± 1.60) vs. (8.33 ± 1.41)]mmol/l, p = 0.034 and [(7.43 ± 1.47) vs. (6.53 ± 1.21)]mmol/l, p=0.017, respectively.

CONCLUSIONS

To our knowledge, this is the first report of mutation detection in patients with clinically suspected FH by NGS in Singapore. While percentage of mutations is similar to other countries, the spectrum locally differs.

An enquiry based on a standardised questionnaire into knowledge, awareness and preferences concerning the care of familial hypercholesterolaemia among primary care physicians in the Asia-Pacific region: the "Ten Countries Study"

OBJECTIVE

To determine physicians' knowledge, awareness and preferences regarding the care of familial hypercholesterolaemia (FH) in the Asia-Pacific region.

SETTING

A formal questionnaire was anonymously completed by physicians from different countries/regions in the Asia-Pacific. The survey sought responses relating to general familiarity, awareness of management guidelines, identification (clinical characteristics and lipid profile), prevalence and inheritance, extent of elevation in risk of cardiovascular disease (CVD) and practice on screening and treatment.

PARTICIPANTS

Practising community physicians from Australia, Japan, Malaysia, South Korea, Philippines, Hong Kong, China, Vietnam and Taiwan were recruited to complete the questionnaire, with the UK as the international benchmark.

PRIMARY OUTCOME

An assessment and comparison of the knowledge, awareness and preferences of FH among physicians in 10 different countries/regions.

RESULTS

1078 physicians completed the questionnaire from the Asia-Pacific region; only 34% considered themselves to be familiar with FH. 72% correctly described FH and 65% identified the typical lipid profile, with a higher proportion of physicians from Japan and China selecting the correct FH definition and lipid profile compared with those from Vietnam and Philippines. However, less than half of the physician were aware of national or international management guidelines; this was significantly worse than physicians from the UK (35% vs 61%, p<0.001). Knowledge of prevalence (24%), inheritability (41%) and CVD risk (9%) of FH were also suboptimal. The majority of the physicians considered laboratory interpretative commenting as being useful (81%) and statin therapy as an appropriate cholesterol-lowering therapy (89%) for FH management.

CONCLUSIONS

The study identified important gaps, which are readily addressable, in the awareness and knowledge of FH among physicians in the region. Implementation of country-specific guidelines and extensive work in FH education and awareness programmes are imperative to improve the care of FH in the region.

Achilles tendon xanthomas are associated with the presence and burden of subclinical coronary atherosclerosis in heterozygous familial hypercholesterolemia: A pilot study

BACKGROUND AND AIMS

Achilles tendon xanthomas (ATX) are a sign of long-term exposure to high blood cholesterol in familial hypercholesterolemia (FH) patients, which have been associated with cardiovascular disease. We evaluated the ATX association with the presence and extent of subclinical coronary atherosclerosis in heterozygous FH patients.

METHODS

102 FH patients diagnosed by US-MEDPED criteria (67% with genetically proven FH), with median LDL-C 279 mg/dL (interquartile range: 240; 313), asymptomatic for cardiovascular disease, underwent computed tomography angiography and coronary artery calcium (CAC) quantification. Subclinical coronary atherosclerosis was quantified by CAC, segment-stenosis (SSS) and segment-involvement (SIS) scores. Adjusted Poisson regression was used to assess the association of ATX with subclinical atherosclerosis burden as continuous variables.

RESULTS

Patients with ATX (n = 21, 21%) had higher LDL-C and lipoprotein(a) [Lp(a)] concentrations as well as greater CAC scores, SIS and SSS (p < 0.05). After adjusting for age, sex, smoking, hypertension, previous statin use, HDL-C, LDL-C and Lp(a) concentrations, there was an independent positive association of ATX presence with CAC scores (β = 1.017, p < 0.001), SSS (β = 0.809, p < 0.001) and SIS (β = 0.640, p < 0.001).

CONCLUSIONS

ATX are independently associated with the extension of subclinical coronary atherosclerosis quantified by tomographic scores in FH patients.

Phenotype vs. genotype in severe familial hypercholesterolemia: what matters most for the clinician?

PURPOSE OF REVIEW

Familial hypercholesterolemia is associated with a high lifetime risk of atherosclerotic cardiovascular disease (ASCVD). However, this risk is variable. This review evaluates recent evidence related to ASCVD risk stratification in familial hypercholesterolemia considering aspects of phenotype and genotype.

RECENT FINDINGS

The heterogeneity in clinical, laboratory characteristics, and in ASCVD risk in both homozygous and heterozygous familial hypercholesterolemia individuals in part can be attributed to the type of molecular defect. In most individuals with LDL cholesterol more than 190 mg/dl, a familial hypercholesterolemia-causing variant is not encountered, however, when present, a variant implicates an even higher ASCVD risk for such individuals. Previous ASCVD events, elevated blood lipoprotein(a), cutaneous markers of cholesterol deposit are among other factors that indicate a higher ASCVD risk in familial hypercholesterolemia individuals underlying a more severe form of the phenotype.

SUMMARY

Both clinical and genetic parameters help identify higher ASCVD risk among severe familial hypercholesterolemia individuals.

Value of the Definition of Severe Familial Hypercholesterolemia for Stratification of Heterozygous Patients

Familial hypercholesterolemia (FH) is characterized by high low-density lipoprotein (LDL) cholesterol with co-dominant transmission and high risk of cardiovascular disease (CVD), although with high variability among subjects. Currently, CVD stratification tools for heterozygous FH (HeFH) are not available. A definition of severe HeFH has been recently proposed by the International Atherosclerosis Society (IAS), but it has not been validated. Our study aims to see clinical characteristics and prevalence of CVD in subjects defined as severe HeFH by IAS criteria. Probable or definite HeFH introduced in the Dyslipidemia Registry of Spanish Arteriosclerosis Society were analyzed by the IAS criteria. Univariate and multivariate analysis was used to assess the association of CVD with the IAS criteria. About 1,732 HeFH cases were analyzed. Severe HeFH had higher prevalence of familial history of CVD, personal history of tendon xanthomas, LDL cholesterol, and CVD than nonsevere HeFH. A total of 656 (77.1%) and 441 (50.1%) of men and women, respectively, fulfilled the IAS criteria of severe HeFH. In the univariate analysis, subjects defined as severe HeFH showed odds ratio 3.016 (95% CI 3.136 to 4.257, p <0.001) for CVD. However, when traditional risk factors were included in the multivariate analysis, only the presence of cholesterol >400 mg/dl had a statistically significant association with CVD odds ratio 8.76 (95% CI 3.90 to 19.69, p <0.001). In conclusion, the IAS definition of severe HeFH is not significantly associated with CVD when adjusted for classic risk factors. Risk stratification in HeFH is an important issue, but the proposed criteria do not seem to solve this problem.

The Molecular Genetic Background of Familial Hypercholesterolemia: Data From the Slovak Nation-Wide Survey

Familial hypercholesterolemia (FH) is most frequently caused by LDLR or APOB mutations. Therefore, the aim of our study was to examine the genetic background of Slovak patients suspected of FH. Patients with clinical suspicion of FH (235 unrelated probands and 124 family relatives) were recruited throughout Slovakia during the years 2011-2015. The order of DNA analyses in probands was as follows: 1. APOB mutation p.Arg3527Gln by real-time PCR method, 2. direct sequencing of the LDLR gene 3. MLPA analysis of the LDLR gene. We have identified 14 probands and 2 relatives with an APOB mutation p.Arg3527Gln, and 89 probands and 75 relatives with 54 different LDLR mutations. Nine of LDLR mutations were novel (i.e. p.Asp90Glu, c.314-2A>G, p.Asp136Tyr, p.Ser177Pro, p.Lys225_Glu228delinsCysLys, p.Gly478Glu, p.Gly675Trpfs*42, p.Leu680Pro, p.Thr832Argfs*3). This is the first study on molecular genetics of FH in Slovakia encompassing the analysis of whole LDLR gene. Genetic etiology of FH was confirmed in 103 probands (43.8 %). Out of them, 86.4 % of probands carried the LDLR gene mutation and remaining 13.6 % probands carried the p.Arg3527Gln APOB mutation.

Multiple large xanthomas: A case report

A 23-year-old male patient presented with multiple large masses in his elbows, buttocks, knees, Achilles tendons, feet, shoulders and hands. The large masses in the elbows and buttocks measured ~6×5×5 cm and ~7×5×4 cm, respectively. The patient presented with an elevated level of low-density lipoprotein cholesterol, and had been previously diagnosed with homozygous familial hypercholesterolemia (FH) and multiple xanthomas. Local surgical excisions were performed to remove the massive xanthomas from the elbows and buttocks, and histological analysis of the surgical specimens confirmed the previous diagnosis of homozygous FH (HoFH). The aim of the present study was to report a rare case of HoFH coinciding with multiple, large and widely-distributed xanthomas and to discuss the clinical characteristics, in order to provide a better understanding of xanthomas and FH.

Defining severe familial hypercholesterolaemia and the implications for clinical management: a consensus statement from the International Atherosclerosis Society Severe Familial Hypercholesterolemia Panel

Familial hypercholesterolaemia is common in individuals who had a myocardial infarction at a young age. As many as one in 200 people could have heterozygous familial hypercholesterolaemia, and up to one in 300 000 individuals could be homozygous. The phenotypes of heterozygous and homozygous familial hypercholesterolaemia overlap considerably; the response to treatment is also heterogeneous. In this Review, we aim to define a phenotype for severe familial hypercholesterolaemia and identify people at highest risk for cardiovascular disease, based on the concentration of LDL cholesterol in blood and individuals' responsiveness to conventional lipid-lowering treatment. We assess the importance of molecular characterisation and define the role of other cardiovascular risk factors and advanced subclinical coronary atherosclerosis in risk stratification. Individuals with severe familial hypercholesterolaemia might benefit in particular from early and more aggressive cholesterol-lowering treatment (eg, with PCSK9 inhibitors). In addition to better tailored therapy, more precise characterisation of individuals with severe familial hypercholesterolaemia could improve resource use.

The Impact of Lipoprotein-Associated Oxidative Stress on Cell-Specific Microvesicle Release in Patients with Familial Hypercholesterolemia

Objective. Microvesicles (MVs) are small cell-derived particles shed upon activation. Familial hypercholesterolemia (FH) particularly when associated with Achilles tendon xanthomas (ATX) predisposes to atherosclerosis, possibly through oxLDL-C interaction with the CD36 receptor. To investigate the hypothesis that MVs derived from cells involved in atherosclerosis are increased in FH and that CD36 expressing MVs (CD36+ MVs) may be markers of oxLDL-C-induced cell activation, cell-specific MVs were measured in FH patients with and without ATX and their association with atherogenic lipid profile was studied. Approach and Results. Thirty FH patients with and without ATX and twenty-three controls were included. Plasma concentrations of MVs and CD36+ MVs derived from platelets (PMVs), erythrocytes (ErytMVs), monocytes (MMVs), and endothelial cells (EMVs), as well as tissue factor-positive cells (TF+ MVs), were measured by flow cytometry. Total MVs, MMVs, EMVs, ErytMVs, and TF+ MVs were significantly increased in FH patients, compared to controls. CD36+ MVs derived from endothelial cells and monocytes were significantly higher in FH patients and oxLDL-C predicted all the investigated cell-specific CD36+ MVs in FH patients with ATX. Conclusions. MVs derived from cells involved in atherosclerosis were increased in FH and may contribute to elevated atherothrombosis risk. The increased cell-specific CD36+ MVs observed in FH may represent markers of oxLDL-C-induced cell activation.

Elevated atherosclerosis-related gene expression, monocyte activation and microparticle-release are related to increased lipoprotein-associated oxidative stress in familial hypercholesterolemia

Objective

Animal and in vitro studies have suggested that hypercholesterolemia and increased oxidative stress predisposes to monocyte activation and enhanced accumulation of oxidized LDL cholesterol (oxLDL-C) through a CD36-dependent mechanism. The aim of this study was to investigate the hypothesis that elevated oxLDL-C induce proinflammatory monocytes and increased release of monocyte-derived microparticles (MMPs), as well as up-regulation of CD36, chemokine receptors and proinflammatory factors through CD36-dependent pathways and that this is associated with accelerated atherosclerosis in subjects with heterozygous familial hypercholesterolemia (FH), in particular in the presence of Achilles tendon xanthomas (ATX).

Approach and Results

We studied thirty FH subjects with and without ATX and twenty-three healthy control subjects. Intima-media thickness (IMT) and Achilles tendon (AT) thickness were measured by ultrasonography. Monocyte classification and MMP analysis were performed by flow cytometry. Monocyte expression of genes involved in atherosclerosis was determined by quantitative PCR. IMT and oxLDL-C were increased in FH subjects, especially in the presence of ATX. In addition, FH subjects had elevated proportions of intermediate CD14++CD16+ monocytes and higher circulating MMP levels. Stepwise linear regression identified oxLDL-C, gender and intermediate monocytes as predictors of MMPs. Monocyte expression of pro-atherogenic and pro-inflammatory genes regulated by oxLDL-C-CD36 interaction was increased in FH, especially in ATX+ subjects. Monocyte chemokine receptor CX₃CR1 was identified as an independent contributor to IMT.

Conclusions

Our data support that lipoprotein-associated oxidative stress is involved in accelerated atherosclerosis in FH, particularly in the presence of ATX, by inducing pro-inflammatory monocytes and increased release of MMPs along with elevated monocyte expression of oxLDL-C-induced atherosclerosis-related genes.

Xanthomas: clinical and pathophysiological relations

BACKGROUND

Xanthomas are well circumscribed lesions in the connective tissue of the skin, tendons or fasciae that predominantly consist of foam cells; these specific cells are formed from macrophages as a result of an excessive uptake of low density lipoprotein (LDL) particles and their oxidative modification.

RESULTS

Until recently, xanthelasma was considered to be only a cosmetic lesion; however, according to the results of recent prospective studies it is connected with an increased cardiovascular risk and reduced average lifespan. Pathogenetic mechanisms involved in the development of xanthomas resemble early stages of atherogenesis. In clinical practice, xanthomas can signalise various congenital or acquired dyslipidemias. The most prevalent form of xanthomas is xanthelasma palpebrarum. Tendinous and tuberous xanthomas are typical for autosomal dominant hypercholesterolemia, as well as for some rare conditions, such as cerebrotendinous xanthomatosis and familial β-sitosterolemia. In patients with familial hypercholesterolemia, the presence of tendinous xanthomas has been shown to be associated with a two to four times higher risk for cardiovascular disease. Eruptive xanthomas are skin manifestations of a severe hypertriglyceridemia and implicate an elevated risk for acute pancreatitis or type 2 diabetes mellitus. Xanthoma striatum palmare is pathognomic for primary dysbetalipoproteinemia, whereas diffuse plane xanthomas are frequently associated with paraproteinemia and lymphoproliferative disorders.

CONCLUSION

Thorough familiarity with the clinical presentation of xanthomas helps in the diagnosis and follow-up of different forms of dyslipidemia. Moreover, xanthelasma palpebrarum, the most prevalent form of xanthomas, is connected with increased risk of atherothrombotic disease independently of conventional cardiovascular risk factors. To fully understand the pathogenesis, further experimental and clinical research is required.