Clinical expression of familial hypercholesterolemia in clusters of mutations of the LDL receptor gene that cause a receptor-defective or receptor-negative phenotype

Consensus document on diagnosis and management of familial hypercholesterolemia from the Italian Society for the Study of Atherosclerosis (SISA)

AIMS

Familial Hypercholesterolemia (FH) is a genetic disorder of lipoprotein metabolism that causes an increased risk of premature atherosclerotic cardiovascular disease (ASCVD). Although early diagnosis and treatment of FH can significantly improve the cardiovascular prognosis, this disorder is underdiagnosed and undertreated. For these reasons the Italian Society for the Study of Atherosclerosis (SISA) assembled a Consensus Panel with the task to provide guidelines for FH diagnosis and treatment.

DATA SYNTHESIS

Our guidelines include: i) an overview of the genetic complexity of FH and the role of candidate genes involved in LDL metabolism; ii) the prevalence of FH in the population; iii) the clinical criteria adopted for the diagnosis of FH; iv) the screening for ASCVD and the role of cardiovascular imaging techniques; v) the role of molecular diagnosis in establishing the genetic bases of the disorder; vi) the current therapeutic options in both heterozygous and homozygous FH. Treatment strategies and targets are currently based on low-density lipoprotein cholesterol (LDL-C) levels, as the prognosis of FH largely depends on the magnitude of LDL-C reduction achieved by lipid-lowering therapies. Statins with or without ezetimibe are the mainstay of treatment. Addition of novel medications like PCSK9 inhibitors, ANGPTL3 inhibitors or lomitapide in homozygous FH results in a further reduction of LDL-C levels. LDL apheresis is indicated in FH patients with inadequate response to cholesterol-lowering therapies.

CONCLUSION

FH is a common, treatable genetic disorder and, although our understanding of this disease has improved, many challenges still remain with regard to its identification and management.

Genetic heterogeneity of familial hypercholesterolaemia in two populations from two different countries

BACKGROUND

Familial hypercholesterolemia (FH) is a genetically determined monogenic disorder of predominantly autosomal dominant inheritance. A number of studies on differences in the genetic profile of patients with FH have demonstrated the importance of a more substantive evaluation of genetic features. The aim of this study was to evaluate the genetic profile of patients with clinical FH among Italian and Russian patients.

METHODS

We included 144 Italian and 79 Russian FH patients; clinical diagnosis was based on the same criteria. Patients were divided in: positive to genetic test (one causative variant), inconclusive (only variants of uncertain clinical significance [VUS]), and negative (with likely benign/benign variants, heterozygous variants in LDLRAP1 gene, or without causative variants).

RESULTS

The genetic test was positive in 76.4 % of the Italian patients and in 49.4 % of the Russian patients. The presence of VUS alone was detected in 7.6 % and in 19.0 % (p < 0.001), respectively. Among patients with positive genetic diagnosis, pre-treatment LDL-C levels were higher in the Russian cohort (353.5 ± 111.3 vs. 302.7 ± 52.1 mg/dL, p = 0.009), as well as the percentage of treated patients (53.8 % vs. 14.5 %, p < 0.001) and the prevalence of premature coronary heart disease (12.8 % vs. 3.6 %, p = 0.039). Among patients carrying only VUS, mean pre-treatment LDL-C levels were similar between the cohorts (299.5 ± 68.1 vs. 295.3 ± 46.8 mg/dL, p = 0.863). Among pathogenic/likely pathogenic variants and VUS, only 5 % and 4 % was shared between the two cohorts, respectively.

CONCLUSION

The genetic background of patients clinically diagnosed with FH in two different countries is characterized by high variability.

Electronic health record-based facilitation of familial hypercholesterolaemia detection sensitivity of different algorithms in genetically confirmed patients

Aims

Familial hypercholesterolaemia (FH) is a disorder of LDL cholesterol clearance, resulting in increased risk of cardiovascular disease. Recently, we developed a Dutch Lipid Clinic Network (DLCN) criteria-based algorithm to facilitate FH detection in electronic health records (EHRs). In this study, we investigated the sensitivity of this and other algorithms in a genetically confirmed FH population.

Methods and results

All patients with a healthcare insurance-related coded diagnosis of 'primary dyslipidaemia' between 2018 and 2020 were assessed for genetically confirmed FH. Data were extracted at the time of genetic confirmation of FH (T1) and during the first visit in 2018-2020 (T2). We assessed the sensitivity of algorithms on T1 and T2 for DLCN ≥ 6 and compared with other algorithms [familial hypercholesterolaemia case ascertainment tool (FAMCAT), Make Early Diagnoses to Prevent Early Death (MEDPED), and Simon Broome (SB)] using EHR-coded data and using all available data (i.e. including non-coded free text). 208 patients with genetically confirmed FH were included. The sensitivity (95% CI) on T1 and T2 with EHR-coded data for DLCN ≥ 6 was 19% (14-25%) and 22% (17-28%), respectively. When using all available data, the sensitivity for DLCN ≥ 6 was 26% (20-32%) on T1 and 28% (22-34%) on T2. For FAMCAT, the sensitivity with EHR-coded data on T1 was 74% (67-79%) and 32% (26-39%) on T2, whilst sensitivity with all available data was 81% on T1 (75-86%) and 45% (39-52%) on T2. For Make Early Diagnoses to Prevent Early Death MEDPED and SB, using all available data, the sensitivity on T1 was 31% (25-37%) and 17% (13-23%), respectively.

Conclusions

The FAMCAT algorithm had significantly better sensitivity than DLCN, MEDPED, and SB. FAMCAT has the best potential for FH case-finding using EHRs.

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

AIMS

Patients with familial hypercholesterolaemia (FH) are at increased risk of cardiovascular disease (CVD) due to extremely high circulating LDL cholesterol (LDL-C) concentrations. Our objective was to study the effect of the type of LDL receptor (LDLR) mutation on the incidence of major adverse cardiovascular events (MACEs).

METHODS AND RESULTS

This was a multinational prospective cohort study, which included patients with heterozygous FH aged 18-65 years, without a prior history of CVD, and carrying a pathogenic or likely pathogenic variant in the LDLR gene. A total of 2131 patients (20 535person-years of follow-up) were included in the study, including 1234 subjects carrying a defective mutation in the LDLR and 897 subjects carrying a null mutation. During the follow-up, a first MACE occurred in 79 cases (6%) in the defective group and in 111 cases (12%) in the null group. The mean baseline LDL-C concentration was 17% higher in the null group than in the defective group (7.90 vs. 6.73 mmoL/L, P < 0.0001). In a Cox regression model corrected for traditional cardiovascular risk factors, the presence of a null mutation was associated with a hazard ratio of 2.09 (1.44-3.05), P = 0.0001.

CONCLUSION

Carriers of a null mutation have an independent ∼2-fold increased risk of incident MACE compared with patients carrying a defective mutation. This study highlights the importance of genetic screening in FH in order to improve patient care.

Genetic diversity in Kashubs: the regional increase in the frequency of several disease-causing variants

Differential distribution of genetic variants’ frequency among human populations is caused by the genetic drift in isolated populations, historical migrations, and demography. Some of these variants are identical by descent and represent founder mutations, which — if pathogenic in nature — lead to the increased frequency of otherwise rare diseases. The detection of the increased regional prevalence of pathogenic variants may shed light on the historical processes that affected studied populations and can help to develop effective screening and diagnostic strategies as a part of personalized medicine. Here, we discuss the specific genetic diversity in Kashubs, the minority group living in northern Poland, reflected in the biased distribution of some of the repetitively found disease-causing variants. These include the following: (1) c.662A > G (p.Asp221Gly) in LDLR, causing heterozygous familial hypercholesterolemia; (2) c.3700_3704del in BRCA1, associated with hereditary breast and ovarian cancer syndrome; (3) c.1528G > C (p.Glu510Gln) in HADHA, seen in long-chain 3-hydroxy acyl-CoA dehydrogenase (LCHAD) deficiency, and (4) c.1032delT in NPHS2, associated with steroid-resistant nephrotic syndrome.

Lack of phenotypic additive effect of familial defective apolipoprotein B3531 in familial hypercholesterolaemia

Familial defective apolipoprotein (apo) B (FDB) and familial hypercholesterolaemia (FH) are the two common genetic conditions that cause hypercholesterolaemia. R3531C mutation of the APOB gene is a rare cause of FDB. Individuals with both FDB and FH are rare. A 51-year-old man with hypercholesterolaemia (11.4 mmol/L) and his family were studied. Low-density lipoprotein (LDL) receptor (LDLR) and APOB genes were analysed by direct sequencing. LDL of four subjects were studied in a fibroblast LDL receptor-binding displacement assay. We found a mutation of the LDLR gene (p.Y398X) in the proband and in four other family members: the p.R3531C APOB gene mutation was also found in the proband, his father and his children. The proband and his son were thus compound heterozygotes for both FH and FDB. Double heterozygotes did not show higher cholesterol levels compared to carriers of LDLR gene mutation alone. LDL from one of the carriers of the p.R3531C alone exhibited a binding ability, which was similar to a normal subject. This is the first report in Italy of the p.R3531C mutation, and our results show that this mutation has no effect in LDLR p.Y398X/APOB p.R3531C double heterozygotes.

Zebrafish as an Emerging Model for Dyslipidemia and Associated Diseases

Dyslipidemia related diseases such as hyperlipidemia and atherosclerosis are the leading cause of death in humans. While cellular and molecular basis on the pathophysiology of dyslipidemia has been extensively investigated over decades, we still lack comprehensive understanding on the etiology of dyslipidemia due to the complexity and the innate multimodality of the diseases. While mouse has been the model organism of choice to investigate the pathophysiology of human dyslipidemia, zebrafish, a small freshwater fish which has traditionally used to study vertebrate development, has recently emerged as an alternative model organism. In this review, we will provide comprehensive perspective on zebrafish as a model organism for human dyslipidemia; we will discuss the attributes of zebrafish as a model, and compare the lipid metabolism in zebrafish and humans. In addition, we will summarize current landscape of zebrafish-based dyslipidemia research.

How registers could enhance knowledge and characterization of genetic dyslipidaemias: The experience of the LIPIGEN in Italy and of other networks for familial hypercholesterolemia

Familial hypercholesterolemia (FH) is a common genetic disorder of lipid metabolism, still underdiagnosed and undertreated in the general population. Pathology registers could play a crucial role in the creation of a comprehensive and integrated global approach to cover all aspects of this disease. Systematic data collection of patients affected by FH has increased dramatically worldwide in the past few years. Moreover, results from registers already established for the longest time showed their potentialities in the implementation of the knowledge of FH, comparing country-specific approaches and providing real-world data about identification, management and treatment of FH individuals in the clinical practice. The potential fields of research through registers are related to the deepening of the genetic basis of disease, the study of genotype-phenotype correlation, the local adaption and implementation of diagnostic algorithms, the comparison of pharmacological approaches and treatment gaps in real-life clinical practice, the evaluation of specific subpopulations, and the identification of factors modifying cardiovascular disease risk. Registers could become also a valid resource for other rare dyslipidaemias, contributing towards the evidence-based enhancement in the worldwide care of uncommon diseases.

Long term follow-up of genetically confirmed patients with familial hypercholesterolemia treated with first and second-generation statins and then with PCSK9 monoclonal antibodies

BACKGROUND AND AIMS

In Italy, the clinical and genetic characteristics of familial hypercholesterolemia (FH) have been extensively assessed in various lipid clinics, although no studies on long-term cardiovascular outcomes in heterozygous patients (He-FH) have been conducted. This study evaluated the incidence of atherosclerotic cardiovascular disease (ASCVD) in He-FH before and after a long-term period of lipid-lowering treatments to ascertain the interference of other risk factors.

METHODS

A total of 294 genetically characterised He-FH subjects from 1989 to 2019 were retrospectively analysed. General characteristics, lipid profiles, ASCVD prevalence, and ultrasound carotid atherosclerosis assessment were evaluated. Primary end points were ASCVD outcomes and the percentage of patients reaching recommended LDL-C targets.

RESULTS

During follow-up, despite a significant improvement in plasma lipid profiles, the ESC/EAS 2016 and 2019 recommended LDL cholesterol (LDL-C) goals were attained in only a few patients treated with anti-PCSK9 monoclonal antibodies added to the maximum tolerated oral therapy with statins plus ezetimibe. Forty-seven subjects had an ASCVD event before starting lipid-lowering therapy (LLT). During follow-up (median 13 years) on LLT, 28 patients had a first ASCVD event and 16 had recurrent ASCVD. In basal conditions and during follow-up, higher LDL-C levels were associated with increased ASCVD risk (p < 0.001). Prevention of recurrent ASCVD events was recorded with a long-term reduction of LDL-C below 100 mg/dl with statins plus ezetimibe.

CONCLUSIONS

PCSK9 inhibition is the only therapeutic option to achieve LDL-C goals as recommended for He-FH and can prevent ASCVD events as reported in large clinical trials. Long-term treatment with statins and ezetimibe seems to be effective at preventing ASCVD recurrence when LDL-C is maintained below 130 and 100 mg/dL for primary and secondary prevention, respectively.

Genetic analysis of familial hypercholesterolemia in Asian Indians: A single-center study

BACKGROUND

Familial hypercholesterolemia (FH), an autosomal codominant disorder characterized by very high low-density lipoprotein cholesterol, is strongly associated with premature coronary artery disease.

OBJECTIVES

Molecular landscape of FH in Asian Indians is not well studied, although this ethnic group comprises a large proportion of the world population. Knowledge of mutations in these groups is useful for identifying persons affected with FH, saving their lives, and cascade screening in their relatives.

METHODS

Potential cases of FH (n = 100) were identified by criteria adapted for the Indian population from Dutch Lipid Clinic Network criteria. Pathogenic variants were analyzed in LDLR, APOB 100 (exons 26 and 29), PCSK9, and APOE genes using Sanger sequencing and multiplex ligation-dependent probe amplification technique. Cases in whom there were no pathogenic variants were tested by next-generation sequencing using a targeted panel of genes.

RESULTS

Thirty-eight pathogenic variants were identified in 47 of 100 unrelated probands. Of these variants, 33 were identified in LDLR, 3 in APOB, and 2 in PCSK9 genes. Ten pathogenic variants were novel. Mutations were detected in 91.4% of those subjects classified as definite, 40% as probable, and in 18.8% as possible FH cases based on modified Dutch Lipid Clinic Network criteria. A likely founder mutation in intron 10 (c.1587-1G>A) of LDLR gene was observed in 6 North Indian families. The conventional pathogenic variants in APOB and PCSK9 genes and those previously reported in LDLR gene among Asian Indians were not detected in this cohort.

CONCLUSION

This study demonstrates genetic heterogeneity of FH in India. The variants observed were different from those described in Western populations. Next-generation sequencing technology helped identify new mutations in APOB gene, suggesting that in less-studied populations, it is better to sequence the whole gene rather than test for specific mutations.

Functional analysis of six uncharacterised mutations in LDLR gene

BACKGROUND AND AIMS

Familial hypercholesterolemia (FH) is a primary hyperlipemia. It is an autosomal dominant genetic disorder of lipoproteins metabolism mainly caused by mutations in the low density lipoprotein receptor gene (LDLR). We aimed to investigate the functional impact on the low density lipoprotein receptor (LDLR) activity of six uncharacterised variants located in the coding region of the LDLR gene, namely c.428G > T, c.640T > C, c.1708C > T, c.1736A > T, c.1981C > G and c.2114C > G (NM_000527.4) and to attempt to define their clinical status.

METHODS

Functional studies were carried out using site-directed mutagenesis techniques and expression of LDLR protein in vitro. Results were correlated with clinical data and in silico analyses in order to assess the physiopathological role of these variants.

RESULTS

This work provides functional information about 6 uncharacterised mutations in LDLR.

CONCLUSIONS

The six variants studied here appeared to affect the LDLR function in vitro to different degrees, ranging from receptors with normal to slightly reduced activity to receptors exhibiting less than 10% of the wild-type activity. According to these studies and The American College of Medical Genetics and Genomics (ACMG) Standards and Guidelines, two variants could be classified as "Likely Benign" (p.(Ala705Gly) and p.(Leu570Phe)), three variants as "Pathogenic" (p.(Asp579Val), p.(Cys143Phe) and p.(Trp214Arg)) and one variant as "Likely Pathogenic" (p.(Pro661Ala)).

In search of a genetic explanation for LDLc variability in an FH family: common SNPs and a rare mutation in MTTP explain only part of LDL variability in an FH family

We previously identified a highly consanguineous familial hypercholesterolemia (FH) family demonstrating segregation of the JD Bari mutation in the LDL receptor as well as a putative cholesterol-lowering trait. We aimed to identify genes related to the latter effect. LDL cholesterol (LDLc) values were normalized for FH affectation status, age, and gender. Using genome-wide SNP data, we examined whether known SNPs gleaned from a genome-wide association study could explain the variation observed in LDLc. Four individuals with markedly reduced LDL levels underwent whole exome sequencing. After prioritizing all potential mutations, we identified the most promising candidate genes and tested them for segregation with the lowering trait. We transfected a plasmid carrying the top candidate mutation, microsomal triglyceride transfer protein (MTTP) R634C, into COS-7 cells to test enzymatic activity. The SNP score explained 3% of the observed variability. MTTP R634C showed reduced activity (49.1 nmol/ml) compared with the WT allele (185.8 nmol/ml) (P = 0.0012) and was marginally associated with reduced LDLc in FH patients (P = 0.05). Phenotypic variability in a FH pedigree can only partially be explained by a combination of common SNPs and a rare mutation and a rare variant in the MTTP gene. LDLc variability in FH patients may have nongenetic causes.

Effects of Genetic Variants Associated with Familial Hypercholesterolemia on Low-Density Lipoprotein-Cholesterol Levels and Cardiovascular Outcomes in the Million Veteran Program

Background

Familial hypercholesterolemia (FH) is characterized by inherited high levels of low-density lipoprotein cholesterol (LDL-C) and premature coronary heart disease (CHD). Over a thousand low-frequency variants in LDLR, APOB and PCSK9 have been implicated in FH but few have been examined at the population level. We aim to estimate the phenotypic effects of a subset of FH variants on LDL-C and clinical outcomes among 331,107 multi-ethnic participants.

Methods

We examined the individual and collective association between putatively pathogenic FH variants included on the MVP biobank array and the maximum LDL-C level over an interval of 15 years (maxLDL). We assessed the collective effect on clinical outcomes by leveraging data from 61.7 million clinical encounters.

Results

We found 8 out of 16 putatively pathogenic FH variants with ≥30 observed carriers to be significantly associated with elevated maxLDL (9.4-80.2 mg/dL). Phenotypic effects were similar for European and African Americans despite substantial differences in carrier frequencies. Based on observed effects on maxLDL, we identified a total of 748 carriers (1:443) who had elevated maxLDL (36.5±1.4 mg/dL, p=1.2×10-152), and higher prevalence of clinical diagnoses related to hypercholesterolemia and CHD in a phenome-wide scan. Adjusted for maxLDL, FH variants collectively associated with higher prevalence of CHD (odds ratio, 1.59 [95% CI 1.36-1.86], p=1.1×10-8) but not peripheral artery disease.

Conclusions

The distribution and phenotypic effects of putatively pathogenic FH variants were heterogeneous within and across variants. More robust evidence of genotype-phenotype associations of FH variants in multi-ethnic populations is needed to accurately infer at-risk individuals from genetic screening.

Spectrum of mutations of familial hypercholesterolemia in the 22 Arab countries

BACKGROUND AND AIMS

Familial hypercholesterolemia (FH) is an inherited genetic disorder of lipid metabolism characterized by a high serum LDL-cholesterol profile and xanthoma formation, and FH increases the risk of premature atherosclerosis and cardiovascular disease (CVD). Mutations in the low-density lipoprotein (LDLR), apolipoprotein B (APOB), proprotein convertase subtilisin/kexin 9 (PCSK9), and LDLRAP1 genes have been associated with FH. Although FH is a major risk for CVD, the disease prevalence and its underlying molecular basis in the 22 Arab countries are still understudied. This study aimed to analyze all peer-reviewed studies related to the prevalence of FH and its causative mutations in the 22 Arab countries.

METHODS

We searched five literature databases (Scopus, Science Direct, Web of Science, PubMed, and Google Scholar) from inception until June 2018, using all possible search terms to capture all of the genetic and prevalence data related to Arab patients with FH.

RESULTS

A total of 5,484 titles and abstracts were identified; 51 studies met our inclusion criteria for the final systematic review. Fifty-one mutations in Arab patients with FH were identified in only eight Arab countries; 47 were identified in the LDLR gene, two in the PCSK9 gene, and two in LDLRAP1 gene. Twenty mutations in the LDLR gene were distinctive to Arab patients. A few studies reported prevalence estimates, ranging from 0.4% to 6.8%.

CONCLUSIONS

This is the first systematic review to dissect the up-to-date status of the genetic epidemiology of Arab patients with FH. It seems that FH is underdiagnosed and that its prevalence is understudied due to the dearth of published information about Arab patients with FH. Therefore, there is a need for well-controlled genetic epidemiological studies on Arab patients with FH.

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.

Upregulated expression of human cathelicidin LL-37 in hypercholesterolemia and its relationship with serum lipid levels

Dyslipidemia in patients with hypercholesterolemia has been recently linked to increased human cathelicidin LL-37 (LL-37) serum concentration. We tested a hypothesis that upregulated expression of LL-37 gene in peripheral blood leucocytes is involved in dyslipidemia in patients with hypercholesteremia. Patients with hypercholesterolemia were used in the study. Expression of LL-37 and human glyceraldehyde-3-phosphate dehydrogenase in peripheral blood leucocytes were quantified by real-time RT-PCR. Serum LL-37 concentration was estimated by enzyme-linked immunosorbent assay. Serum lipid levels were assessed by absorptiometry in all cases. Patients with hypercholesterolemia as compared to control ones were characterized by (a) an up-regulation of LL-37 gene expression in peripheral blood leucocytes with parallel increase of serum LL-37 concentration and (b) an increase of serum total and low-density lipoprotein cholesterol concentrations. Patients with hypercholesterolemia after a treatment with atorvastatin calcium 20 mg daily as compared to that patients before the treatment: an down-regulation of LL-37 gene expression in peripheral blood leucocytes with parallel decrease of serum LL-37 concentration. We also found significant correlation between serum LL-37 and high-density lipoprotein cholesterol levels (r = 0.7290, P < 0.0001). The results suggest that hypercholesterolemia is associated with an increased LL-37 gene expression in peripheral blood leucocytes. The correlation between serum LL-37 and high-density lipoprotein cholesterol levels suggests that LL-37 may play a key role in regulation of cholesterol levels in hypercholesterolemia.

The Genetic Link Between Diabetes and Atherosclerosis

Epidemiological studies have indicated that the risk of atherothrombotic coronary artery disease (CAD) is higher in patients with diabetes, but these results have not been consistently observed across clinical trials. To address this apparent discrepancy, we can apply the results of genome-wide association studies (GWAS) to provide a better understanding of the shared genetic architecture of diabetes and atherothrombotic CAD. For instance, a large GWAS has identified 16 novel loci that are associated with both diabetes and atherothrombotic CAD. These genetic variants may also be used to assess potential causal relationships reported in observational studies and clinical trials through Mendelian randomization analyses. For example, several Mendelian randomization analyses have shown that diabetes is associated with CAD independent of other risk factors (odds ratio [OR]: 1.63, 95% confidence interval [CI]: 1.23-2.07; P = 0.002). Furthermore, Mendelian randomization analyses can provide more insight into the perceived risk of diabetes among patients without diabetes receiving statin therapy. Here, genetically lower activity of HMG-CoA reductase (HMGCR) was associated with a modest increase in diabetes (OR per allele: 1.02, 95% CI: 1.00-1.05). These results highlight the biological mechanisms that link diabetes with the use of statins. In addition, this work illustrates the great potential value of genetic studies to clarify the mechanistic relationships among atherosclerotic vascular disease, dysglycemia, and diabetes. More research is needed to delineate and subsequently better understand the genetic links between diabetes and atherosclerosis.

Targeting microsomal triglyceride transfer protein and lipoprotein assembly to treat homozygous familial hypercholesterolemia

Homozygous familial hypercholesterolemia (HoFH) is a polygenic disease arising from defects in the clearance of plasma low-density lipoprotein (LDL), which results in extremely elevated plasma LDL cholesterol (LDL-C) and increased risk of atherosclerosis, coronary heart disease, and premature death. Conventional lipid-lowering therapies, such as statins and ezetimibe, are ineffective at lowering plasma cholesterol to safe levels in these patients. Other therapeutic options, such as LDL apheresis and liver transplantation, are inconvenient, costly, and not readily available. Recently, lomitapide was approved by the Federal Drug Administration as an adjunct therapy for the treatment of HoFH. Lomitapide inhibits microsomal triglyceride transfer protein (MTP), reduces lipoprotein assembly and secretion, and lowers plasma cholesterol levels by over 50%. Here, we explain the steps involved in lipoprotein assembly, summarize the role of MTP in lipoprotein assembly, explore the clinical and molecular basis of HoFH, and review pre-clinical studies and clinical trials with lomitapide and other MTP inhibitors for the treatment of HoFH. In addition, ongoing research and new approaches underway for better treatment modalities are discussed.

Homozygous familial hypercholesterolemia in childhood: Genotype-phenotype description, established therapies and perspectives

Familial hypercholesterolemia (FH) is a co-dominantly inherited disorder of plasma lipoprotein metabolism. The prevalence of heterozygous FH (HeFH) is between 1/500 and 1/200 whereas that of homozygous form (HoFH) is about 1/1,000,000. Diagnosis is based on cutaneous xanthomas and untreated levels of LDL-cholesterol over 500 mg/dl before 10 years of age. Life expectancy, without treatment, does not exceed 20 years of age. The aim of this study is to characterise in details a cohort of 8 HoFH paediatric patients in order to illustrate all the current therapeutic options and to add some clinical and genetic information about this rare disease. We collected demographic, clinical, biological, imaging and genotype details. Furthermore, clinical and biochemical response to different treatment methods was retrospectively evaluated. All patients had genetically proven HoFH. All patients were subject to a lipid-lowering diet and medical treatment (except one), three patients underwent a liver transplant and one an hepatocytes infusion. Medical treatment was well tolerated with a median reduction of 44% and 47% in LDL-Cholesterol and Total Cholesterol respectively. The hepatocytes transplant produced a further, though slight, decrease in cholesterol levels as opposed to medical therapy alone. Transplanted patients normalized their cholesterol levels. Since the very high cardiovascular risk, HoFH requires immediate diagnosis, treatment and monitoring. Nowadays, the use of statins remains the cornerstone of medical therapy and liver transplantation is the possibly curative therapy. Besides, high hopes are pinned in new drugs (antibody targeting PCSK9, Mipomersen and Lomitapide) and stem cells.

Type of LDLR mutation and the pharmacogenetics of familial hypercholesterolemia treatment

Familial hypercholesterolemia (FH) is an autosomal dominant disease mainly caused by mutations in the low-density lipoprotein receptor (LDLR) gene. FH patients present a wide variability regarding response to drugs and they are usually undertreated. Here, we review studies that evaluated the association between the type of LDLR mutation and the response to lipid-lowering therapy. The main findings were that patients with a null LDLR mutation had: higher baseline LDL-C, higher LDL-C after drug therapy, lower proportion of patients within the LDL-C target value and higher frequencies of CVD. Thus, we conclude that FH patients harboring a null mutation have a trend to an increased risk, even if diagnosis is early established and lipid-lowering treatment instituted. It is suggested that these individuals may benefit from the use of newly approved lipid-lowering agents.

The impact of LDLR function on fibroblast growth factor 21 levels

CONTEXT

Fibroblast growth factor 21 (FGF21) has been described to have beneficial effects on glucose and lipid metabolism, and FGF21 analogs are currently evaluated in phase 1 trials. However, the complete spectrum of effects and regulators of FGF21 is yet partly elucidated. Recent studies have shown that FGF21 plays a role in transmembrane cholesterol transport.

OBJECTIVE

We set out to examine the association between FGF21 and LDLR mediated transmembrane cholesterol transport, by comparing FGF21 levels in patients with genetically impaired LDLR function and unaffected relatives. Secondly, we explored whether the severity of the LDLR mutation was associated with FGF21 levels.

METHODS

We performed a cross-sectional study in carriers of an LDLR mutation and their unaffected relatives. Subjects were eligible if they participated in the Dutch national screening program for familial hypercholesterolemia (FH), were 18-55 years old, and were carrier of a pathogenic LDLR mutation with an untreated LDL-C level below the 75(th) or above the 90(th) percentile of the general population, or did not carry an FH mutation. The outcome measure was the level of FGF21, which was assessed using ELISA.

RESULTS

We included 224 carriers of an LDLR mutation and 148 unaffected relatives. FGF21 levels were lower in LDLR mutation carriers compared to unaffected relatives (median [interquartile range]: 96.92 [60.80-174.05] versus 136.98 [77.34-219.47] pg/mL, respectively; p = 0.08), but after adjusting for potential confounders, there was no association between LDLR mutations and FGF21 levels (p = 0.70). Neither, did we find a relationship between the severity of LDLR mutations and FGF21 levels (p = 0.51, after adjustment for potential confounders).

CONCLUSIONS

We showed that levels of FGF21 are not different in patients with and without LDLR mutations, which suggests that decreased LDLR expression does not have a negative effect on FGF21 levels. Given the potential beneficial effects of FGF21 analogs on lipids and lipoproteins in a phase 1 study, we deem this of great interest for future treatment options for FH patients.

Systematic analysis of variants related to familial hypercholesterolemia in families with premature myocardial infarction

Familial hypercholesterolemia (FH) is an oligogenic disorder characterized by markedly elevated low-density lipoprotein cholesterol (LDLC) levels. Variants in four genes have been reported to cause the classical autosomal-dominant form of the disease. FH is largely under-diagnosed in European countries. As FH increases the risk for coronary artery disease (CAD) and myocardial infarction (MI), it might be specifically overlooked in the large number of such patients. Here, we systematically examined the frequency of potential FH-causing variants by exome sequencing in 255 German patients with premature MI and a positive family history for CAD. We further performed co-segregation analyses in an average of 5.5 family members per MI patient. In total, we identified 11 potential disease-causing variants that co-segregate within the families, that is, 5% of patients with premature MI and positive CAD family history had FH. Eight variants were previously reported as disease-causing and three are novel (LDLR.c.811G>A p.(V271I)), PCSK9.c.610G>A (p.(D204N)) and STAP1.c.139A>G (p.(T47A))). Co-segregation analyses identified multiple additional family members carrying one of these FH variants and the clinical phenotype of either FH (n=2) or FH and premature CAD (n=15). However, exome sequencing also revealed that some variants in FH genes, which have been reported to cause FH, do not co-segregate with FH. The data reveal that a large proportion of FH patients escape the diagnosis, even when they have premature MI. Hence, systematic molecular-genetic screening for FH in such patients may reveal a substantial number of cases and thereby allow a timely LDLC-lowering in both FH/MI patients as well as their variant-carrying family members.

Familial Hypercholesterolemia in Greek children and their families: genotype-to-phenotype correlations and a reconsideration of LDLR mutation spectrum

OBJECTIVE

Familial Hypercholesterolemia (FH) is a common lipid metabolism disease, resulting in premature atherosclerosis, even from childhood. We aimed to define the genetic basis of FH in children and their families, to refine the spectrum of Low-Density Lipoprotein Receptor gene (LDLR) mutations and identify genotype-to-phenotype correlations in patients of Greek origin.

METHODS

LDLR was analyzed in 561 patients from 262 families, by whole-gene sequencing.

RESULTS

Children with identified LDLR mutations showed higher lipid levels compared to non-carriers. Molecular analysis identified a mutation in 53.4% of index cases. Twenty six LDLR mutations were identified, including 19 point mutations, 2 nonsense mutations, 3 splice site mutations and 2 small insertions. Amongst patients with common mutations, carriers of c.1646G > A and c.1285G > A showed higher lipid levels, whereas carriers of c.858C > A and c.81C > G showed a milder phenotype.

CONCLUSIONS

The spectrum of LDLR mutations in Greece is refined and expanded, with more patients analyzed by whole-gene sequencing. Although a quick screening method is feasible for the Greek population, whole-gene sequencing is essential to identify rare variants. Children with border line lipid levels and a family history of hypercholesterolemia should be considered for molecular diagnosis, since carriers of certain mutations show milder phenotypes and may be missed during clinical diagnosis.

Upregulated expression of human alpha-defensins 1, 2 and 3 in hypercholesteremia and its relationship with serum lipid levels

Human alpha-defensins are natural antimicrobial peptides of neutrophils evolved in host defense reactions and circulating nonstressed alpha-defensins may be associated with serum lipid levels. The aim of this work was to examine whether the expression of alpha-defensins 1, 2 and 3 genes are changed and whether this changes are reversed following treatment in patients with hypercholesteremia. A total of 40 individuals of hypercholesteremia group were studied, compared with 40 individuals of normal control group. Protein levels and gene expression levels of alpha-defensins 1, 2 and 3 were significantly higher in patients with hypercholesteremia compared with subjects in normal control group. In patients with hypercholesteremia, protein levels of alpha-defensins 1, 2 and 3 correlated positively with the levels of total cholesterol and low-density lipoprotein cholesterol. Protein levels and gene expression levels of alpha-defensins 1, 2 and 3 were decreased significantly after a treatment with atorvastatin calcium 20mg daily compared with the patients before the treatment. Our results suggest that the expression of alpha-defensins 1, 2 and 3 genes is involved in dyslipidemia in patients with hypercholesteremia.

Genetic and biochemical analyses in dyslipidemic patients undergoing LDL apheresis

OBJECTIVE

Familial hypercholesterolemia (FH) can be due to mutations in LDLR, PCSK9, and APOB. In phenotypically defined patients, a subset remains unresponsive to lipid-lowering therapies and requires low density-lipoprotein (LDL) apheresis treatment. In this pilot study, we examined the genotype/phenotype relationship in patients with dyslipidemia undergoing routine LDL apheresis.

DESIGN

LDLR, APOB, and PCKS9 were analyzed for disease-causing mutations in seven patients undergoing routine LDL apheresis. Plasma and serum specimens were collected pre- and post-apheresis and analyzed for lipid concentrations, Lp(a) cholesterol, and lipoprotein particle concentrations (via NMR).

RESULTS

We found that four patients harbored LDLR mutations and of these, three presented with xanthomas. While similar reductions in LDL-cholesterol (LDL-C), apolipoprotein B, and LDL particles (LDL-P) were observed following apheresis in all patients, lipid profile analysis revealed the LDLR mutation-positive cohort had a more pro-atherogenic profile (higher LDL-C, apolipoprotein B, LDL-P, and small LDL-P) pre-apheresis.

CONCLUSION

Our data show that not all clinically diagnosed FH patients who require routine apheresis have genetically defined disease. In our small cohort, those with LDLR mutations had a more proatherogenic phenotype than those without identifiable mutations. This pilot cohort suggests that patients receiving the maximum lipid lowering therapy could be further stratified, based on genetic make-up, to optimize treatment.

Presence and type of low density lipoprotein receptor (LDLR) mutation influences the lipid profile and response to lipid-lowering therapy in Brazilian patients with heterozygous familial hypercholesterolemia

OBJECTIVES

Familial hypercholesterolemia (FH) is an autosomal dominant disease caused mainly by LDLR mutations. This study assessed the influence of the presence and type of LDLR mutation on lipid profile and the response to lipid-lowering therapy in Brazilian patients with heterozygous FH.

METHODS

For 14 ± 3 months, 156 patients with heterozygous FH receiving atorvastatin were followed. Coding sequences of the LDLR gene were bidirectionally sequenced, and the type of LDLR mutations were classified according to their probable functional class.

RESULTS

The frequencies of the types of LDLR mutations were: null-mutation (n = 40, 25.6%), defective-mutation (n = 59, 37.8%), and without an identified mutation (n = 57, 36.6%). Baseline total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were higher in patients carrying a null mutation (9.9 ± 1.9 mmol/L, 7.9 ± 1.7 mmol/L), compared to those with a defective (8.9 ± 2.2 mmol/L, 7.0 ± 2.0 mmol/L), or no mutation (7.9 ± 1.9 mmol/L, 5.8 ± 1.9 mmol/L) (p < 0.001). After treatment, the proportion of patients attaining an LDL-C<3.4 mmol/L was significantly different among groups: null (22.5%), defective (27.1%), and without mutations (47.4%) (p = 0.02). The presence of LDLR mutations was independently associated with higher odds of not achieving the LDL-C cut-off (OR 9.07, 95% CI 1.41-58.16, p = 0.02).

CONCLUSIONS

Our findings indicate that the presence and type of LDLR mutations influence lipid profile and response to lipid-lowering therapy in Brazilian patients with heterozygous FH. Thus, more intensive care with pharmacological therapeutics should be performed in patients who have a molecular analysis indicating the presence of a LDLR mutation.

Autosomal dominant hypercholesterolemia: needs for early diagnosis and cascade screening in the tunisian population

Autosomal dominant hypercholesterolemia (ADH) is characterized by an isolated elevation of plasmatic low-density lipoprotein (LDL), which predisposes to premature coronary artery disease (CAD) and early death. ADH is largely due to mutations in the low-density lipoprotein receptor gene (LDLR), the apolipoprotein B-100 gene (APOB), or the proprotein convertase subtilisin/kexin type 9 (PCSK9). Early diagnosis and initiation of treatment can modify the disease progression and its outcomes. Therefore, cascade screening protocol with a combination of plasmatic lipid measurements and DNA testing is used to identify relatives of index cases with a clinical diagnosis of ADH. In Tunisia, an attenuated phenotypic expression of ADH was previously reported, indicating that the establishment of a special screening protocol is necessary for this population.

Coronary computed tomographic angiographic findings in asymptomatic patients with heterozygous familial hypercholesterolemia and null allele low-density lipoprotein receptor mutations

Heterozygous familial hypercholesterolemia (HeFH) can be associated with early coronary artery disease (CAD) in asymptomatic patients. The objectives of the present study were to assess the prevalence and magnitude of subclinical CAD in patients with HeFH using coronary computed tomographic angiography (CCTA) and to determine the clinical and genetic profile of those at the greatest risk of CAD. The study included 50 consecutive patients with HeFH diagnosed according to the Dutch Lipid Clinic Network criteria and a control group of 70 healthy subjects. The findings from CCTA for the patients with HeFH were compared with those from the control group, who had been referred for CCTA as a part of a preventive medical examination. In 82% of the patients with HeFH, genetic DNA was screened for low-density lipoprotein receptor (LDLR) gene mutations using a microarray. CCTA revealed a significantly greater Agatston calcium score in the study group than in the control group (260 vs 46; p = 0.002). The prevalence of CAD in the patients with HeFH was 48%. It was significant in 26%, involving mainly the proximal segments of the coronary arteries. In the control group, the prevalence of CAD was 33% and was significant in 5% (p <0.05 for prevalence and severity of CAD compared to patients with HeFH). In those with HeFH, increased age, null allele LDLR mutations, and low high-density lipoprotein blood levels at diagnosis showed a statistically significant association with CAD (p <0.05). In conclusion, patients with HeFH present with a greater prevalence, extension, and severity of subclinical CAD than the general population. Increased age, low high-density lipoprotein levels, and LDLR null allele mutations are related to the occurrence of CAD. CCTA has emerged as a useful technique for the screening of subclinical CAD in patients with HeFH.

Leucine 10 allelic variant in signal peptide of PCSK9 increases the LDL cholesterol-lowering effect of statins in patients with familial hypercholesterolaemia

BACKGROUND AND AIMS

In the normal population, carriers of an additional leucine residue in a stretch of nine leucines in the signal peptide of PCSK9 (L10) have lower total (TC) and low-density lipoprotein cholesterol (LDL-C) than homozygotes for the wild-type allele (L9/L9). A similar effect was detected in familial hypercholesterolaemia (FH) patients with the p.C681X mutation of LDL-receptor (LDLR). We investigated the effect of L10 variant on basal lipid profile and response to statins in molecularly characterised FH patients.

METHODS AND RESULTS

Plasma lipids were determined in 322 FH patients screened for the L9/L10/L11 polymorphism and in a subgroup of 54 patients carrying the same LDLR mutation (p.Q474HfsX63). Plasma lipids were also determined in 42 FH patients carrying the L10 variant and in a parallel group of 42 FH patients, L9/L9 homozygotes, matched for gender, age, type of LDLR gene mutation, as well as for type, dose and duration of statin treatment. In FH patients, no difference in the basal plasma TC and LDL-C levels was observed between carriers of L10 variant (L9/L10+L10/L10) and L9/L9 homozygotes. The same was true in FH patients carrying the p.Q474HfsX63 LDLR mutation. In the subgroups of statin-treated patients, the reduction of TC and LDL-C was greater in carriers of L10 (-34.0% and -42.5%, respectively) than in L9/L9 homozygotes (-27.5% and -34.3%, respectively) (P<0.001).

CONCLUSION

The variant L10 of the leucine repeats in PCSK9 signal peptide is to be considered as a factor capable of modulating the lipid-lowering effects of statins in FH.

Nutraceutical pill containing berberine versus ezetimibe on plasma lipid pattern in hypercholesterolemic subjects and its additive effect in patients with familial hypercholesterolemia on stable cholesterol-lowering treatment

Background

Although statins (STs) are drugs of first choice in hypercholesterolemic patients, especially in those at high cardiovascular risk, some of them are intolerant to STs or refuse treatment with these drugs. In view of this, we have evaluated the lipid-lowering effect of a nutraceutical pill containing berberine (BBR) and of ezetimibe, as alternative treatments, in monotherapy or in combination, in 228 subjects with primary hypercholesterolemia (HCH), with history of STs intolerance or refusing STs treatment. In addition, since PCSK9 was found up-regulated by STs dampening their effect through an LDL receptors (LDLRs) degradation, and BBR suppressed PCSK9 expression in cellular studies, we supplemented the stable lipid-lowering therapy of 30 genotype-confirmed Familial Hypercholesterolemia heterozygotes (HeFH) with BBR, searching for a further plasma cholesterol reduction. Plasma lipid pattern was evaluated at baseline and during treatments.

Results

In HCH subjects the nutraceutical pill resulted more effective than EZE in lowering LDL cholesterol (−31.7% vs −25.4%, P < 0.001) and better tolerated. On treatment, LDL-C level below 3.36 mmol/L (≤130 mg/dl) was observed in 28.9% of subjects treated with the nutraceutical pill and 11.8% of those treated with EZE (P <0.007). In the group treated with EZE the subjects carrying the G allele of the g.1679 C > G silent polymorphism of NPC1L1 gene showed a higher response to EZE than homozygous for the common allele (GG + CG: LDL-C −29.4±5.0%, CC −23.6±6.5%, P <0.001). Combined treatment with these drugs was as effective as STs in moderate doses (LDL cholesterol −37%, triglycerides −23%). In HeFH patients the addition of BBR resulted in LDL cholesterol reductions inversely related to those induced by the stable therapy (r = −0.617, P <0.0001), with mean 10.5% further decrease.

Conclusions

The alternative treatments tested in our HCH subjects were rather effective and safe. The findings in HeFH patients suggest that BBR might act in vivo increasing expression and stability of LDLRs and/or suppressing PCSK9 expression.

The molecular basis of familial hypercholesterolemia in the Czech Republic: spectrum of LDLR mutations and genotype-phenotype correlations

BACKGROUND

Familial hypercholesterolemia (FH), a major risk for coronary heart disease, is predominantly associated with mutations in the genes encoding the low-density lipoprotein receptor (LDLR) and its ligand apolipoprotein B (APOB).

RESULTS

In this study, we characterize the spectrum of mutations causing FH in 2239 Czech probands suspected to have FH. In this set, we found 265 patients (11.8%) with the APOB mutation p.(Arg3527Gln) and 535 patients (23.9%) with a LDLR mutation. In 535 probands carrying the LDLR mutation, 127 unique allelic variants were detected: 70.1% of these variants were DNA substitutions, 16.5% small DNA rearrangements, and 13.4% large DNA rearrangements. Fifty five variants were novel, not described in other FH populations. For lipid profile analyses, FH probands were divided into groups [patients with the LDLR mutation (LDLR+), with the APOB mutation (APOB+), and without a detected mutation (LDLR-/APOB-)], and each group into subgroups according to gender. The statistical analysis of lipid profiles was performed in 1722 probands adjusted for age in which biochemical data were obtained without FH treatment (480 LDLR+ patients, 222 APOB+ patients, and 1020 LDLR-/APOB- patients). Significant gradients in i) total cholesterol (LDLR+ patients > APOB+ patients = LDLR-/APOB- patients) ii) LDL cholesterol (LDLR+ patients > APOB+ patients = LDLR-/APOB- patients in men and LDLR+patients > APOB+ patients >LDLR-/APOB- patients in women), iii) triglycerides (LDLR-/APOB- patients > LDLR+ patients > APOB+ patients), and iv) HDL cholesterol (APOB+ patients > LDLR-/APOB- patients = LDLR+ patients) were shown.

CONCLUSION

Our study presents a large set of Czech patients with FH diagnosis in which DNA diagnostics was performed and which allowed statistical analysis of clinical and biochemical data.

Mechanisms and genetic determinants regulating sterol absorption, circulating LDL levels, and sterol elimination: implications for classification and disease risk

This review integrates historical biochemical and modern genetic findings that underpin our understanding of the low-density lipoprotein (LDL) dyslipidemias that bear on human disease. These range from life-threatening conditions of infancy through severe coronary heart disease of young adulthood, to indolent disorders of middle- and old-age. We particularly focus on the biological aspects of those gene mutations and variants that impact on sterol absorption and hepatobiliary excretion via specific membrane transporter systems (NPC1L1, ABCG5/8); the incorporation of dietary sterols (MTP) and of de novo synthesized lipids (HMGCR, TRIB1) into apoB-containing lipoproteins (APOB) and their release into the circulation (ANGPTL3, SARA2, SORT1); and receptor-mediated uptake of LDL and of intestinal and hepatic-derived lipoprotein remnants (LDLR, APOB, APOE, LDLRAP1, PCSK9, IDOL). The insights gained from integrating the wealth of genetic data with biological processes have important implications for the classification of clinical and presymptomatic diagnoses of traditional LDL dyslipidemias, sitosterolemia, and newly emerging phenotypes, as well as their management through both nutritional and pharmaceutical means.

The treatment of hypercholesterolemic children: efficacy and safety of a combination of red yeast rice extract and policosanols

BACKGROUND AND AIMS

The prevention of cardiovascular risk, as occurs in lipoprotein disorders, is required since childhood. Aim of the study was to evaluate, in a group of children affected by primary dyslipidemia, the efficacy, tolerability and safety of a short-term treatment with a dietary supplement containing red yeast rice extract and policosanols.

METHODS AND RESULTS

40 children affected by heterozygous Familial Hypercholesterolemia (FH) (n=24) and Familial Combined Hyperlipidemia (FCH) (n=16), aged 8-16 years, were enrolled in a double-blind, randomized, placebo-controlled, cross-over trial. After a 4-week run-in period with only dietary advice, children received a dietary supplement containing 200mg red yeast rice extract, corresponding to 3mg of monacolins, and 10mg policosanols once-daily and placebo for 8 weeks, separated by a 4-week washout period. Lipid profile was assessed after each treatment period. The dietary supplement, compared with the placebo, significantly reduced total cholesterol by 18.5% (p<0.001), LDL-C levels by 25.1% (p<0.001), and apolipoprotein B by 25.3% (p<0.001) when patients were considered as a whole group. Similar results were obtained when FH and FCH were considered separately and no significant difference between groups was detected. No significant differences were observed in HDL-C and apolipoprotein A-I levels. No adverse effects were detected when liver and muscular enzymes (AST, ALT, and CK) were determined.

CONCLUSIONS

The treatment with a dietary supplement containing red yeast rice extract and policosanols has been for the first time successfully employed in hypercholesterolemic children. Results indicate this strategy as an effective, safe and well tolerated in a short-term trial.

Preemptive liver transplantation in a child with familial hypercholesterolemia

Familial hypercholesterolemia is an autosomal codominant disorder associated with markedly elevated plasma concentration of LDL-cholesterol and increased cardiovascular risk. Homozygous patients have rapid development of atherosclerosis with death from cardiovascular disease even in childhood. Life-long recurrent apheresis to reduce plasma LDL-cholesterol is considered the gold standard for treatment. Liver transplantation can be curative for this condition, but is usually only considered after the development of cardiovascular disease. We report a 5.5-yr-old child initially misdiagnosed with heterozygous familial hypercholesterolemia and treated by low-fat diet only. In view of persistent hypercholesterolemia and development of xanthomatosis, new molecular studies indicated the presence of two different mutations in the LDL receptor gene, with one being a deletion of two exons not identifiable with standard sequencing analysis. Recurrent plasma apheresis in combination with statins lowered, but did not normalize plasma LDL-cholesterol levels. It caused progressive reduction of the size of xanthomas and prevented the development of vascular complications. After two yr, liver transplantation normalized LDL-cholesterol levels and completely resolved the skin lesions. Preemptive liver transplantation is a definitive cure of familial homozygous hypercholesterolemia and might be more effective if performed before development of vascular complications.

Moderate phenotypic expression of familial hypercholesterolemia in Tunisia

BACKGROUND

Autosomal Dominant Hypercholesterolemia (ADH) is an autosomal dominant disease caused by mutations in the low density lipoprotein receptor (LDLR), apolipoprotein B (APOB), and proprotein convertase subtilisin/kexin type 9 (PCSK9) genes. Xanthomas and coronary heart diseases (CHD) at an early age are the major clinical manifestations of the disease.

METHODS

16 families with familial hypercholesterolemia from different regions in Tunisia participated in the study. Mutations within the LDLR gene were screened through DNA sequencing. Lipids values were measured by standard enzymatic methods.

RESULTS

We present here thirty five homozygotes and fifty six heterozygotes. Homozygotes presented extensive xanthomatosis, variable clinical manifestations of CHD, and total cholesterol levels in males and females of 17.26+/-4.18 and 17.64+/-2.59 mmol/L respectively. HDL-cholesterol levels were 0.62+/-0.24 and 1.00+/-0.61 mmol/L for males and females, respectively. None of the heterozygotes had tendon xanthomas (except for one female aged 62), eight had corneal arcus, and nine developed CHD mean between 46 and 88 years old. Total cholesterol levels in males and females ranged from 4.60 to 8.90 and from 4.30 to 10.50 mmol/L, respectively.

CONCLUSION

Tunisian FH heterozygotes are characterized by a moderate clinical and biological expression of the disease.

Plasma non-cholesterol sterols: a useful diagnostic tool in pediatric hypercholesterolemia

Current guidelines strongly recommend the identification of genetic forms of hypercholesterolemia (HC) during childhood.The usefulness of non-cholesterol sterols (NCS) in the diagnosis of genetic HC has not been fully explored. Plasma NCS were measured by gas chromatography/mass spectrometry (GC/MS) in 113 children with hypercholesterolemia affected by: autosomal dominant hypercholesterolemia (ADH), familial combined hyperlipidemia(FCHL), polygenic hypercholesterolemia (PHC), and in 79 controls to evaluate: i) plasma NCS profile in different genetic HC and ii) the usefulness of NCS for the diagnosis of HC beyond current clinical criteria. ADH was characterized by raised lathosterol/total cholesterol (TC) and reduced phytosterols/TC ratios, indicative of increased cholesterol synthesis. FCHL showed a slight increase of lathosterol/TC ratio, whereas PHC showed increased phytosterols/TC ratios, indicative of increased cholesterol absorption. In a post hoc discriminant analysis of patients with HC, lipid values correctly classified the 73% (14 of 19) of ADH, whereas the inclusion of plasma sterols allowed the correct identification of all 19 patients with ADH. FCHL was not differentiated from PHC (62 versus 69%).In conclusion, NCS measurement showed that cholesterol plasma levels are related to the cholesterol synthesis in ADH and to cholesterol absorption in PHC. NCS improve the detection of ADH in pediatric patients, whereas FCHL diagnosis is not improved.