Autosomal Recessive Hypercholesterolemia Long-Term Cardiovascular Outcomes

BACKGROUND Autosomal recessive hypercholesterolemia (ARH) is a rare lipid disorder characterized by premature atherosclerotic cardiovascular disease (ASCVD). There are sparse data for clinical management and cardiovascular outcomes in ARH. OBJECTIVES Evaluation of changes in lipid management, achievement of low-density lipoprotein cholesterol (LDL-C) goals and cardiovascular outcomes in ARH. METHODS Published ARH cases were identified by electronic search. All corresponding authors and physicians known to treat these patients were asked to provide follow-up information, using a standardized protocol. RESULTS We collected data for 52 patients (28 females, 24 males; 31.1 +/- 17.1 years of age…

Familial HDL deficiency due to ABCA1 gene mutations with or without other genetic lipoprotein disorders

Mutations in ABCA1 have been shown to be the cause of Tangier disease (TD) and some forms of familial hypoalphalipoproteinemia (HA), two genetic disorders characterized by low plasma HDL levels. Here we report six subjects with low HDL, carrying seven ABCA1 mutations, six of which are previously unreported. Two mutations (R557X and H160FsX173) were predicted to generate short truncated proteins; two mutations (E284K and Y482C) were located in the first extracellular loop and two (R1901S and Q2196H) in the C-terminal cytoplasmic domain of ABCA1. Two subjects found to be compound heterozygotes for ABCA1 mutations did not have overt clinical manifestations of TD. Three subjects, all with prema…

Additive effect of mutations in LDLR and PCSK9 genes on the phenotype of familial hypercholesterolemia.

Patients homozygous or Compound heterozygous for LDLR mutations or double heterozygous for LDLR and apo B R3500Q mutation have higher LDL-C levels. more extensive xanthomatosis and more severe premature coronary disease (pCAD) than simple heterozygotes for mutations in either these genes or for missense mutations in PCSK9 gene. It is not known whether combined mutations in LDLR and PKCS9 are associated with such a severe phenotype. We sequenced Apo B and PCSK9 genes in two patients with the clinical diagnosis of homozygous FH who were heterozygous for LDLR gene mutations. Proband Z.P. (LDL-C 13.39 mmol/L and pCAD) was heterozygous for an LDLR mutation (p.E228K) inherited from her father (LD…

LDL apheresis in a homozygous familial hypercholesterolemic child aged 4.5.

Preliminary experience with the efficacy and safety of dextran sulfate cellulose low-density lipoprotein (LDL) apheresis for the treatment of a 4.5-year-old girl with homozygous familial hypercholesterolemia and coronary artery disease is reported. The decrease of the most atherogenic apolipoprotein B-containing lipoproteins, low-density lipoprotein (LDL) and lipoprotein(a) (Lp [a]), were in the ranges of 63.1-68.7%, and 52.5-58.6%, respectively. The child tolerated LDL apheresis without any clinically significant complications. Therefore, she was submitted to a long-term program of treatment at intervals of 15 days. The experience suggests the possibility of an early beginning of extracorp…

Seesaw Scale in the Minimal Renormalizable SO(10) Grand Unification

Simple SO(10) Higgs models with the adjoint representation triggering the grand-unified symmetry breaking, discarded a long ago due to inherent tree-level tachyonic instabilities in the physically interesting scenarios, have been recently brought back to life by quantum effects. In this work we focus on the variant with 45_H+126_H in the Higgs sector and show that there are several regions in the parameter space of this model that can support stable unifying configurations with the B-L breaking scale as high as 10^14 GeV, well above the previous generic estimates based on the minimal survival hypothesis. This admits for a renormalizable implementation of the canonical seesaw and makes the s…

Two Italian kindreds carrying the Arg136--Ser mutation of the Apo E gene: development of premature and severe atherosclerosis in the presence of epsilon 2 as second allele.

Abstract Background and Aims: Type III hyperlipoproteinemia, or dysbetalipoproteinemia, is commonly associated with apolipoprotein E2 homozygosity (Cy Background and Aims: 12, Cy Background and Aims: 58). Apo E2-Christchurch (Arg136→Ser), a rare mutation of the Apo E gene, located in the receptor-binding domain of the protein, has been found to be associated in the vast majority of cases of dysbetalipoproteinemia. Methods and Results: This is the first report of two Italian kindreds carrying the Arg136→Ser mutation. One family is a four-generation kindred from Genoa (Liguria, Italy) with a high rate of mortality due to coronary artery disease: the proband was a 51-year-old woman with previo…

Homozygous familial hypercholesterolemia in Italy: Clinical and molecular features

Abstract Background and aims Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disorder characterized by extremely elevated plasma levels of low density lipoprotein cholesterol (LDL-C) and high risk of premature atherosclerotic cardiovascular disease (ASCVD). HoFH is caused by pathogenic variants in several genes, such as LDLR, APOB and PCSK9, responsible for autosomal dominant hypercholesterolemia (ADH), and LDLRAP1 responsible for autosomal recessive hypercholesterolemia (ARH). Aim of this study was the review of the clinical and molecular features of patients with HoFH identified in Italy from 1989 to 2019. Methods Data were collected from lipid clinics and laboratories, …

Molecular diagnosis of hypobetalipoproteinemia: an ENID review.

Abstract Primary hypobetalipoproteinemia (HBL) includes a group of genetic disorders: abetalipoproteinemia (ABL) and chylomicron retention disease (CRD), with a recessive transmission, and familial hypobetalipoproteinemia (FHBL) with a co-dominant transmission. ABL and CRD are rare disorders due to mutations in the MTP and SARA2 genes, respectively. Heterozygous FHBL is much more frequent. FHBL subjects often have fatty liver and, less frequently, intestinal fat malabsorption. FHBL may be linked or not to the APOB gene. Most mutations in APOB gene cause the formation of truncated forms of apoB which may or may be not secreted into the plasma. Truncated apoBs with a size below that of apoB-3…

Spectrum of mutations of the LPL gene identified in Italy in patients with severe hypertriglyceridemia.

Background: Monogenic hypertriglyceridemia (HTG) may result from mutations in some genes which impair the intravascular lipolysis of triglyceride (TG)-rich lipoproteins mediated by the enzyme Lipoprotein lipase (LPL). Mutations in the LPL gene are the most frequent cause of monogenic HTG (familial chylomicronemia) with recessive transmission. Methods: The LPL gene was resequenced in 149 patients with severe HTG (TG>10mmol/L) and 106 patients with moderate HTG (TG>4.5 and <10mmol/L) referred to tertiary Lipid Clinics in Italy. Results: In the group of severe HTG, 26 patients (17.4%) were homozygotes, 9 patients (6%) were compound heterozygotes and 15 patients (10%) were simple heter…

Overview of the current status of familial hypercholesterolaemia care in over 60 countries - The EAS Familial Hypercholesterolaemia Studies Collaboration (FHSC)

PubMed: 30270054

Efficacy and safety of lomitapide in homozygous familial hypercholesterolaemia: the pan-European retrospective observational study

Abstract Aims Lomitapide is a lipid-lowering agent indicated as an adjunct therapy for adult homozygous familial hypercholesterolaemia (HoFH). This study evaluated the medium-term effectiveness and safety of lomitapide in a large cohort of HoFH patients in Europe. Methods and results In a multicentre retrospective, observational study including 75 HoFH patients treated with lomitapide in a real-world clinical setting from 9 European countries, low-density lipoprotein cholesterol (LDL-C) changes, adverse events (AEs), and major adverse cardiovascular events (MACE) were assessed. After a median 19 months (interquartile range 11–41 months) of treatment with a mean dosage of 20 mg of lomitapide…

Long-term efficacy of lipoprotein apheresis and lomitapide in the treatment of homozygous familial hypercholesterolemia (HoFH): a cross-national retrospective survey

Abstract Background Homozygous familial hypercholesterolemia (HoFH) is a rare life-threatening condition that represents a therapeutic challenge. The vast majority of HoFH patients fail to achieve LDL-C targets when treated with the standard protocol, which associates maximally tolerated dose of lipid-lowering medications with lipoprotein apheresis (LA). Lomitapide is an emerging therapy in HoFH, but its place in the treatment algorithm is disputed because a comparison of its long-term efficacy versus LA in reducing LDL-C burden is not available. We assessed changes in long-term LDL-C burden and goals achievement in two independent HoFH patients’ cohorts, one treated with lomitapide in Ita…

Identifying genetic risk variants for coronary heart disease in familial hypercholesterolemia: an extreme genetics approach

Mutations in the low-density lipoprotein receptor (LDLR) gene cause familial hypercholesterolemia (FH), a disorder characterized by coronary heart disease (CHD) at young age. We aimed to apply an extreme sampling method to enhance the statistical power to identify novel genetic risk variants for CHD in individuals with FH. We selected cases and controls with an extreme contrast in CHD risk from 17 000 FH patients from the Netherlands, whose functional LDLR mutation was unequivocally established. The genome-wide association (GWA) study was performed on 249 very young FH cases with CHD and 217 old FH controls without CHD (above 65 years for males and 70 years of age for females) using the Ill…

Lipoprotein(a) Genotype Influences the Clinical Diagnosis of Familial Hypercholesterolemia

: Background Evidence suggests that LPA risk genotypes are a possible contributor to the clinical diagnosis of familial hypercholesterolemia (FH). This study aimed at determining the prevalence of LPA risk variants in adult individuals with FH enrolled in the Italian LIPIGEN (Lipid Transport Disorders Italian Genetic Network) study, with (FH/M+) or without (FH/M-) a causative genetic variant. Methods and Results An lp(a) [lipoprotein(a)] genetic score was calculated by summing the number risk-increasing alleles inherited at rs3798220 and rs10455872 variants. Overall, in the 4.6% of 1695 patients with clinically diagnosed FH, the phenotype was not explained by a monogenic or polygenic cause …

Minimal Flipped SO(10) x U(1) Supersymmetric Higgs Model

We investigate the conditions on the Higgs sector that allow supersymmetric SO(10) grand unified theories (GUT) to break spontaneously to the standard electroweak model (SM) at the renormalizable level. If one considers Higgs representations of dimension up to the adjoint, a supersymmetric standard model vacuum requires in most cases the presence of non-renormalizable (NR) operators. The active role of Planck induced NR operators in the breaking of the gauge symmetry introduces a hierarchy in the mass spectrum at the GUT scale that may be an issue for gauge unification and proton decay. We show that the minimal Higgs scenario that allows for a renormalizable breaking to the SM is obtained b…

Towards a New Minimal SO(10) Unification

We argue that non-supersymmetric SO(10) models based on a renormalizable Higgs sector in which spontaneous symmetry breaking is triggered by the VEVs of a 45-dimensional adjoint and a 126-dimensional tensor representations can provide a potentially realistic yet relatively simple framework for a future robust estimate of the proton lifetime. Following closely the work Phys.Rev.D85, 095014 (2012), arXiv: 1202.0807 [hep-ph] we comment on the gauge unification constraints on the B-L breaking scale and show that there are several regions in the parameter space of the minimal model where the seesaw scale in the phenomenologically favoured ballpark of around 10^13-14 GeV is consistently supported.

Effects of a phytosterol-enriched dairy product on lipids, sterols and 8-isoprostane in hypercholesterolemic patients: a multicenter Italian study.

Abstract Background and aims Plant sterols, added to several food sources, lower serum cholesterol concentrations. Plant sterol-induced cholesterol lowering is paralleled by a mild decrease in plasma levels of the antioxidant β-carotene, the amount of this decrease being considered clinically non-significant. Whether the effect on lipid profile of daily consumption of plant sterol-enriched low-fat fermented milk (FM) is paralleled by a concomitant variation in a reliable marker of the oxidative burden like plasma isoprostane levels is unresolved. Methods and results The effect of plant sterol consumption on plasma lipid and isoprostane levels of hypercholesterolemic patients was evaluated i…

Rapid screening of the LDL receptor point mutation FH-Genoa/Palermo

The LDL-receptor gene point mutation FH-Genoa/Palermo is the most frequent mutation responsible for Familial Hypercholesterolemia in Sicily. The mutation does not introduce or abolish any useful restriction site. We establish a GeneComb™-based strategy to identify this mutation in a population of Sicilian unrelated clinically diagnosed FH probands. The method was very sensitive and specific; 12 out of 90 (13.3%) unrelated FH probands were found to carry the FH-Genoa/Palermo mutation. According to these results, the FH-Genoa/Palermo is the more frequent LDL-receptor gene mutation among the Sicilian FH patients. Moreover FH-Genoa/Palermo is the mutation cluster to date more represented in Sou…

Additional file 1 of Long-term efficacy of lipoprotein apheresis and lomitapide in the treatment of homozygous familial hypercholesterolemia (HoFH): a cross-national retrospective survey

Additional file 1: Table 1. Patients’ genotypes. All mutations were classified according to ACMG guidelines (Chora JR, Medeiros AM, Alves AC, Bourbon M. Analysis of publicly available LDLR, APOB, and PCSK9 variants associated with familial hypercholesterolemia: application of ACMG guidelines and implications for familial hypercholesterolemia diagnosis. Genet Med. 2018;20(6):591-598). For 3 Homozygous LDLR and 1 LDLRAP1 causing mutations were not available and the diagnosis was only on clinical base. *Double Heterozygote patient for mutations in both LDLR (c.373C>T) and PCSK9 (c.60_ 65dupGCTGCT) genes.

Efficacy of Long-Term Treatment of Autosomal Recessive Hypercholesterolemia With Lomitapide: A Subanalysis of the Pan-European Lomitapide Study

Backgroundand aim: Autosomal recessive hypercholesterolemia (ARH) is a rare autosomal recessive disorder of low-density lipoprotein (LDL) metabolism caused by pathogenic variants in the LDLRAP1 gene. Like homozygous familial hypercholesterolemia, ARH is resistant to conventional LDL-lowering medications and causes a high risk of atherosclerotic cardiovascular diseases (ASCVDs) and aortic valve stenosis. Lomitapide is emerging as an efficacious therapy in classical HoFH, but few data are available for ARH.Results: This is a subanalysis carried out on nine ARH patients included in the Pan-European Lomitapide Study. The age at starting lomitapide was 46 (interquartile range (IQR), 39.0–65.5) y…

Spectrum of mutations in Italian patients with familial hypercholesterolemia: New results from the LIPIGEN study

Abstract Background Familial hypercholesterolemia (FH) is an autosomal dominant disease characterized by elevated plasma levels of LDL-cholesterol that confers an increased risk of premature atherosclerotic cardiovascular disease. Early identification and treatment of FH patients can improve prognosis and reduce the burden of cardiovascular mortality. Aim of this study was to perform the mutational analysis of FH patients identified through a collaboration of 20 Lipid Clinics in Italy (LIPIGEN Study). Methods We recruited 1592 individuals with a clinical diagnosis of definite or probable FH according to the Dutch Lipid Clinic Network criteria. We performed a parallel sequencing of the major…

Italian familial defective apolipoprotein B patients share a unique haplotype with other Caucasian patients.

Familial defective apolipoprotein (apo) B-100 together with familial hypercholesterolemia are the two common genetic conditions that cause hypercholesterolemia. Familial defective apolipoprotein B-100 is due to mutations around codon 3500 of the apo B gene. The most-characterized mutation is a G>A transition at nucleotide 10,708 that results in the substitution of arginine by glutamine at codon 3500 (Apo B Arg3500Gln). Two other mutations are caused by a C>T transition, one at nucleotide 10,800 (Apo B Arg3531Cys) and the other at nucleotide 10,707 (apo B Arg3500Trp). In the present study we describe three new Italian cases of familial defective apolipoprotein B-100 (Apo B Arg3500Gln), one f…

Autosomal Recessive Hypercholesterolemia

Abstract Background Autosomal recessive hypercholesterolemia (ARH) is a rare lipid disorder characterized by premature atherosclerotic cardiovascular disease (ASCVD). There are sparse data for clinical management and cardiovascular outcomes in ARH. Objectives Evaluation of changes in lipid management, achievement of low-density lipoprotein cholesterol (LDL-C) goals and cardiovascular outcomes in ARH. Methods Published ARH cases were identified by electronic search. All corresponding authors and physicians known to treat these patients were asked to provide follow-up information, using a standardized protocol. Results We collected data for 52 patients (28 females, 24 males; 31.1 ± 17.1 years…

Corrigendum to "Molecular diagnosis of hypobetalipoproteinemia: An ENID review" [Atherosclerosis 195 (2) (2007) 19-27].

Mitochondrial DNA variations in patients with Type 2 (non-insulin dependent) diabetes mellitus and a Welsh control population

The LDL-receptor gene point mutation FH-Genoa/Palermo is the most frequent mutation responsible for Familial Hypercholesterolemia in Sicily. The mutation does not introduce or abolish any useful restriction site. We establish a GeneComb-based strategy to identify this mutation in a population of Sicilian unrelated clinically diagnosed FH probands. The method was very sensitive and specific; 12 out of 90 (13.3%) unrelated FH probands were found to carry the FH-Genoa/Palermo mutation. According to these results, the FH-Genoa/Palermo is the more frequent LDL-receptor gene mutation among the Sicilian FH patients. Moreover FH-Genoa/Palermo is the mutation cluster to date more represented in Sout…

Structure and prospects of the simplest SO(10) GUTs

We recapitulate the latest results on the class of the simplest SO(10) grand unified models in which the GUT-scale symmetry breaking is triggered by an adjoint Higgs representation. We argue that the minimal survival approximation traditionally used in the GUT- and seesaw-scale estimates tends to be blind to very interesting parts of the parameter space in which some of the intermediate-scale states necessary for non-supersymmetric unification of the SM gauge couplings can be as light as to leave their imprints in the TeV domain. The stringent minimal-survival-based estimates of the B-L scale are shown to be relaxed by as much as four orders of magnitude, thus admitting for a consistent imp…

Familial combined hypolipidemia due to mutations in the ANGPTL3 gene

The role of ANGPTL3 in lipoprotein metabolism emerged from studies in a mutant mouse strain characterized by severe hypotriglyceridemia and carrying a loss-of-function (LOF) mutation of the ANGPTL3 gene. ANGPTL3 was found to inhibit lipoprotein lipase and endothelial lipase. Genome-wide association studies in humans demonstrated the association of ANGPTL3 variants with plasma triglyceride levels and LOF mutations of ANGPTL3 were found in hypotriglyceridemic subjects in population studies. Recently, individuals originally classified as affected by familial hypobetalipoproteinemia were found to be homozygotes/compound heterozygotes for rare LOF mutations of ANGPTL3. They show a striking reduc…

Genetic polymorphisms affecting the phenotypic expression in familial hypercholesterolemia

The clinical expression of heterozygous familial hypercholesterolemia (FH) is highly variable even in patients carrying the same LDL receptor (LDL-R) gene mutation. This variability might be due to environmental factors as well as to modifying genes affecting lipoprotein metabolism. We investigated Apo E (2, 3, 4), MTP (-493G/T), Apo B (-516C/T), Apo A-V (-1131T/C), HL (-514C/T and -250G/A), FABP-2 (A54T), LPL (D9N, N291S, S447X) and ABCA1 (R219K) polymorphisms in 221 unrelated FH index cases and 349 FH relatives with defined LDL-R gene mutations. We found a significant and independent effect of the following polymorphisms on: (i) plasma LDL-C (Apo E, MTP and Apo B); (ii) plasma HDL-C (HL, …

Response to treatment and occurrence of cardiovascular (CV) complications in patients with autosomal recessive hypercholesterolemia (ARH): A retrospective analysis

Mutations in MTP gene in abeta- and hypobeta-lipoproteinemia.

Abstract Familial hypobetalipoproteinemia (FHBL) and abetalipoproteinemia (ABL) are inherited disorders of apolipoprotein B (apo B)-containing lipoproteins that result from mutations in apo B and microsomal triglyceride transfer protein (MTP) genes, respectively. Here we report three patients with severe deficiency of plasma low-density lipoprotein (LDL) and apo B. Two of them (probands F.A. and P.E.) had clinical and biochemical phenotype consistent with ABL. Proband F.A. was homozygous for a minute deletion/insertion (c.1228delCCCinsT) in exon 9 of MTP gene predicted to cause a truncated MTP protein of 412 amino acids. Proband P. E. was heterozygous for a mutation in intron 9 (IVS9-1G>A),…

CLINICAL CHARACTERISTICS AND PLASMA LIPIDS IN SUBJECTS WITH FAMILIAL COMBINED HYPOLIPIDEMIA: A POOLED ANALYSIS

Background. Angiopoietin-like 3 (ANGPTL3) regulates lipoprotein metabolism by modulating extracellular lipases. Loss-of function mutations in ANGPTL3 gene cause familial combined hypolipidemia (FHBL2). The mode of inheritance and hepatic and vascular consequences of FHBL2 have not been fully elucidated. To get further insights on these aspects, we re-evaluated the clinical and the biochemical characteristics of all reported cases of FHBL2. Methods and Results. One hundred fteen FHBL2 individuals carrying 13 different mutations in the ANGPTL3 gene (14 homozygotes, 8 compound heterozygotes and 93 heterozygotes) and 402 controls were considered. Carriers of 2 mutant alleles had undetectable pl…

Familial hypercholesterolemia: The Italian Atherosclerosis Society Network (LIPIGEN)

Background and aims: Primary dyslipidemias are a heterogeneous group of disorders characterized by abnormal levels of circulating lipoproteins. Among them, familial hypercholesterolemia is the most common lipid disorder that predisposes for premature cardiovascular disease. We set up an Italian nationwide network aimed at facilitating the clinical and genetic diagnosis of genetic dyslipidemias named LIPIGEN (LIpid TransPort Disorders Italian GEnetic Network). Methods: Observational, multicenter, retrospective and prospective study involving about 40 Italian clinical centers. Genetic testing of the appropriate candidate genes at one of six molecular diagnostic laboratories serving as nationw…

Worldwide experience of homozygous familial hypercholesterolaemia:retrospective cohort study

[Background]: Homozygous familial hypercholesterolaemia (HoFH) is a rare inherited disorder resulting in extremely elevated low-density lipoprotein cholesterol levels and premature atherosclerotic cardiovascular disease (ASCVD). Current guidance about its management and prognosis stems from small studies, mostly from high-income countries. The objective of this study was to assess the clinical and genetic characteristics, as well as the impact, of current practice on health outcomes of HoFH patients globally.

Spectrum of mutations and phenotypic expression in patients with autosomal dominant hypercholesterolemia identified in Italy.

Abstract Objective To determine the spectrum of gene mutations and the genotype–phenotype correlations in patients with Autosomal Dominant Hypercholesterolemia (ADH) identified in Italy. Methods The resequencing of LDLR , PCSK9 genes and a selected region of APOB gene were conducted in 1018 index subjects clinically heterozygous ADH and in 52 patients clinically homozygous ADH. The analysis was also extended to 1008 family members of mutation positive subjects. Results Mutations were detected in 832 individuals: 97.4% with LDLR mutations, 2.2% with APOB mutations and 0.36% with PCSK9 mutations. Among the patients with homozygous ADH, 51 were carriers of LDLR mutations and one was an LDLR / …

Additional file 2 of Long-term efficacy of lipoprotein apheresis and lomitapide in the treatment of homozygous familial hypercholesterolemia (HoFH): a cross-national retrospective survey

Additional file 2: Figure 1. LDL-C burden according to lomitapide or LA treatment. A Box plot graphs represent the median values of cumulative LDL-C burden in the Lomitapide cohort (dark grey) and in the LA cohort (light grey). For the total LDL-C burden calculation see Methods. P values are adjusted for age at follow-up, untreated LDL-C values and gender. B, C Box plot graphs represent the median values of TC and LDL-C burden at baseline and on-treatment. For baseline and on-treatment TC or LDL-C burden calculation see Methods. Δ% represents TC and LDL-c percent reduction from baseline and is reported with the respective statistical significance. B shows data form Lomitapide cohort whereas…