Search Results (34)

Background/Objectives: The clinical presentation of homozygous familial hypercholesterolemia (HoFH) and severe heterozygous familial hypercholesterolemia (sHeFH) often demonstrates substantial overlap, as low-density lipoprotein cholesterol (LDL-C) levels may fall within similar ranges in both conditions. Methods: In this single-center 10-year retrospective study at the University of Debrecen, Hungary, we present the clinical characteristics of patients with 6 HoFH and 6 sHeFH diagnosed by genetic testing, discuss the diagnostic limitations encountered in clinical practice, and outline the key components of therapeutic management. Results: The mean age at diagnosis was lower in the HoFH group (31.83 ± 19.5 vs. 41.83 ± 15.9 years). The differences in total cholesterol (13.48 ± 7.4 vs. 11.02 ± 3.5 mmol/L) and LDL-C levels (10.89 ± 6.6 vs. 8.58 ± 3.26 mmol/L) between the groups were not statistically significant. Interestingly, vascular complications were more frequent in sHeFH group as well (4 vs. 1 patients). In neither the HoFH nor the sHeFH group were we able to achieve the target LDL-C levels, due in part to the specific features of the reimbursement system, patient and parental preferences, the extremely high baseline LDL-C levels, and certain genetic characteristics. Conclusions: Our findings highlight the importance of genetic testing-based personalized therapy in these specific patient subpopulations. We emphasize that serum LDL-C alone is insufficient to distinguish between HoFH and sHeFH patients, and that therapeutic challenges should be anticipated in both groups arising partly from limited patient adherence as well as from financial constraints. Full article

We previously demonstrated lipid nanoparticle-mediated CRISPR-Cas9 gene editing to disrupt the gene encoding cytochrome P450 oxidoreductase (Cypor), combined with transient administration of acetaminophen (APAP), to repopulate the liver with healthy hepatocytes and rescue a phenylketonuria mouse model. This study aimed to investigate electroporation-mediated delivery of Cypor-targeting CRISPR-Cas9 ribonucleoproteins into wild-type hepatocytes, combined with liver engraftment under APAP treatment, as an in vivo selection approach in a mouse model of homozygous familial hypercholesterolemia (Ldlr^−/−). Electroporation provides higher delivery efficiency compared to lipid nanoparticles. We observed engraftment levels up to 13% engraftment of electroporated Cypor-deficient hepatocytes with indels in the liver of Ldlr^−/− mice after transient APAP administration, while negligible engraftment was observed in no-APAP controls (mean 9% and 2%, respectively, p = 0.0121). The engraftment of Cypor-deficient Ldlr^+/+ hepatocytes was associated with reductions in LDL-cholesterol (18%) and triglycerides (52%) compared to the untransplanted control Ldlr^−/− mice fed a Western diet for 5 weeks, but offered no protection from the development of diet-induced aortic root atherosclerosis or liver steatosis. While biochemical markers for liver damage normalized after discontinuation of APAP, we observed persistent lipid accumulation in the liver of Ldlr^−/− mice grafted with Cypor-deficient Ldlr^+/+ hepatocytes, likely stemming from the impact of Cypor deficiency on cholesterol clearance. Therefore, the combination of CRISPR-Cas9-mediated Cypor knockdown to induce clonal expansion of gene-edited hepatocytes using transient APAP administration is not a viable therapeutic strategy for familial hypercholesterolemia due to the essential role of Cypor in cholesterol metabolism. Unlike findings from phenylketonuria mouse model studies, the loss of Cypor function could not be compensated by unedited native hepatocytes in Ldlr^−/− mice. Collectively, our results demonstrate that electroporation is a viable and informative approach for evaluating gene editing strategies for the treatment of inherited metabolic diseases that affect the liver. Our electroporation procedure revealed that a one-size-fits-all gene editing strategy may not be universally applicable for treating inherited metabolic liver disorders. Tailored gene editing and selection strategies may be needed for different liver disorders. Full article

Our aim was to determine whether rare APOE pathogenic variants (PV) and the common e2/e3/e4 polymorphism were associated with the risk of familial hypercholesterolemia (FH). A total of 431 patients who met the inclusion criteria for FH were next-generation sequenced for the main candidate genes (LDLR, APOB, PCSK9, APOE, LDLRAP1). A total of 139 patients (32%) had a pathogenic variant, including 3 with APOE p.Leu167del. Among the PV-negatives (n = 292), one was homozygous for APOE-e2 and showed a combined phenotype of high low-density lipoprotein cholesterol (LDL-C) and triglycerides (TGs). A total of 165 population controls were also genotyped for the APOE polymorphism. PV-negative patients showed a significantly higher frequency of APOE-e3e4/e4e4 compared to PV-positives (p = 0.006) and to population controls (p = 0.0002, OR = 2.63, 95% CI = 1.57–4.40). APOE-e4e4 patients had significantly higher mean LDL-C compared to the other genotypes (p = 0.047). In conclusion, APOE pathogenic variants were a rare cause of FH in our population, and the APOE-e4 allele was a significant risk factor for being diagnosed with familial hypercholesterolemia in the absence of a pathogenic variant involved in FH. In particular, the APOE-e4e4 genotype was associated with higher LDL-C levels compared to the other genotypes. Full article

Familial hypercholesterolemia is an autosomal hereditary disease defined by an increased level of low-density lipoprotein cholesterol (LDL-C), which predisposes significant risks for premature cardiovascular disorders. We present a family trio study: proband, a 13-year-old Kazakh girl with homozygous familial hypercholesterolemia (HoFH) and her parents. HoFH is much more rare and severe than a heterozygous form of the disorder. HoFH patients generally present with LDL-C levels exceeding 13 mmol/L, resulting in early and life-threatening cardiovascular events within the first decades of life. In cases of neglected treatment, young patients have a risk of death from coronary diseases before the age of 30. The aim of this research was to identify genetic mutations in the affected patient and her parents. Genetic testing was necessary due to highly elevated LDL-C levels and the presence of multiple xanthomas. Targeted next-generation sequencing (NGS) was performed in this study using the Illumina TruSight cardio panel, which targets 174 genes related to cardiac disorders. The girl was diagnosed with HoFH based on the results of genetic testing. A biallelic mutation was observed in exon 3 of the low-density lipoprotein receptor (LDLR): c. 295 G>A (p.Glu99Lys). Sanger sequencing confirmed that the mutant gene was inherited from both parents. After confirming the genetic diagnosis of HoFH, the patient was treated with LDL apheresis and statins. This case report is the first study of HoFH in a pediatric patient from the Central Asian region. Globally, it emphasizes the need for increased clinical awareness among healthcare providers, as early detection and intervention are important for improving outcomes, particularly in pediatric patients with this rare genetic disorder. Full article

Background and Objectives: The proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors evolocumab and alirocumab are recently developed promising drugs used for treatment of familial hypercholesterolemia (FH). This systematic review and meta-analysis aimed to thoroughly evaluate the efficacy and safety of evolocumab and alirocumab among pediatric patients with FH. Materials and Methods: A comprehensive search was conducted in PubMed, Embase, CENTRAL (Cochrane Central Register of Controlled Trials), and ClinicalTrials.gov from inception through July 2024 to identify primary interventional studies among pediatric patients with FH. Meta-analyses were performed if appropriate. Statistics were analyzed using Review Manager version 5.4 and Stata version 16.0. Results: Fourteen articles reporting nine unique studies were included. There were three randomized controlled trials (RCTs) assessing evolocumab or alirocumab involving a total of 320 pediatric patients, one cross-over trial and five single-arm or observational studies. Pooled results showed significant efficacy of evolocumab/alirocumab in reducing low-density lipoprotein cholesterol (LDL-C) (weighted mean difference [WMD]: −37.92%, 95% confidence interval [CI]: −43.06% to −32.78%; I² = 0.0%, p = 0.60), apolipoprotein B (WMD: −33.67%, 95% CI: −38.12% to −29.22%; I² = 0.0%, p = 0.71), and also lipoprotein(a) (WMD: −16.94%, 95% CI: −26.20% to −7.69%; I² = 0.0%, p = 0.71) among pediatric patients with FH. The efficacies of evolocumab/alirocumab on LDL-C reduction within pediatric patients with heterozygous FH (HeFH) were consistent between studies, whereas in patients with homozygous FH (HoFH), it varied dramatically. Pediatric patients with the null/null variant may respond to the treatment. PCSK9 inhibitors were generally well tolerated within most pediatric patients, in line with previous studies among adult populations. Conclusions: The PCSK9 inhibitors evolocumab/alirocumab significantly reduced LDL-C and some other lipid parameters, such as apolipoprotein B, in pediatric patients with HeFH. These drugs may be appropriate as a potential therapy for pediatric patients with HoFH who cannot achieve LDL-C targets with other treatments. Evolocumab/alirocumab was generally well tolerated in the pediatric population. Full article

Familial hypercholesterolemia, a genetic disorder marked by elevated low-density lipoprotein cholesterol (LDL-C), poses significant risks for premature atherosclerosis and cardiovascular diseases, particularly during pregnancy. One of the safe methods of treating this condition in pregnancy is with the use of LDL apheresis. We present a 38-year-old primigravida with homozygous Familial Hypercholesterolemia (HoFH), ischemic cardiomyopathy, and angina pectoris. Two years before conception, extremely elevated lipid levels prompted statin therapy and lifestyle changes. Stent placements followed acute myocardial infarction. When planning pregnancy, statins were discontinued, but lipid levels elevated. LDL apheresis was initiated, achieving a 60% reduction. Throughout pregnancy, 16 LDL apheresis sessions were performed every 14 days, maintaining optimal lipid profiles. A cesarean section was performed in the 38th week of gestation, delivering a healthy infant. The patient resumed statin therapy after 8 months of breastfeeding. The patient maintained cardiovascular health, demonstrating the feasibility of controlled HoFH pregnancies. This case highlights the successful management of HoFH during pregnancy using LDL apheresis, ensuring maternal and fetal well-being. Future research on novel treatments and their safety during pregnancy is essential for refining therapeutic approaches in similar cases. Full article

Background: The diagnosis of familial hypercholesterolemia (FH) in children is primarily based on main criteria including low-density lipoprotein cholesterol (LDL-C) levels, increased in the proband and relatives, and its inheritance. Two other relevant parameters are symptoms, rarely occurring in children, as rare are the FH homozygous patients, and the mutation detection of related genes. The latter allows the final diagnosis, although it is not commonly available. Moreover, the application of diagnostic scores, useful in adults, is poorly applied in children. The aim of this study was to compare the reliability of criteria here applied with different scores, apart from genetic analysis, for FH diagnosis. The latter was then confirmed by genetic analysis. Methods: n. 180 hypercholesterolemic children (age 10.2 ± 4.6 years) showing LDL-C levels ≥95th percentile (age- and sex-related), the dominant inheritance pattern of hypercholesterolemia (including LDL-C ≥95th percentile in one parent), were considered potentially affected by FH and included in the study. The molecular analysis of the LDLR, APOB and PCSK9 genes was applied to verify the diagnostic accuracy. Biochemical and family history data were also retrospectively categorized according to European Atherosclerosis Society (EAS), Simon Broome Register (SBR), Pediatric group of the Italian LIPIGEN (LIPIGEN-FH-PED) and Dutch Lipid Clinic Network (DLCN) criteria. Detailed kindred biochemical and clinical assessments were extended to three generations. The lipid profile was detected by standard laboratory kits, and gene analysis was performed by traditional sequencing or Next-Generation Sequencing (NGS). Results: Among 180 hypercholesterolemic subjects, FH suspected based on the above criteria, 164/180 had the diagnosis confirmed, showing causative mutations. The mutation detection rate (MDR) was 91.1%. The scoring criteria proposed by the EAS, SBR and LIPIGEN-FH-PED (resulting in high probable, possible-defined and probable-defined, respectively) showed high sensitivity (~90%), low specificity (~6%) and high MDR (~91%). It is noteworthy that their application, as a discriminant for the execution of the molecular investigation, would lead to a loss of 9.1%, 9.8% and 9.1%, respectively, of FH-affected patients, as confirmed by the genetic analysis. DLCN criteria, for which LDL-C cut-offs are not specific for childhood, would lead to a loss of 53% of patients with mutations. Conclusions: In the pediatric population, the combination of LDL-C ≥95th percentile in the proband and the dominant inheritance pattern of hypercholesterolemia, with LDL-C ≥95th percentile in one parent, is a simple, useful and effective diagnostic criterion, showing high MDR. This pattern is crucial for early FH diagnosis. EAS, SBR and LIPIGEN-FH-PED criteria can underestimate the real number of patients with gene mutations and cannot be considered strictly discriminant for the execution of molecular analysis. Full article

Familial hypercholesterolemia (FH) is a genetic disorder primarily transmitted in an autosomal-dominant manner. We distinguish two main forms of FH, which differ in the severity of the disease, namely homozygous familial hypercholesterolemia (HoFH) and heterozygous familial hypercholesterolemia (HeFH). The characteristic feature of this disease is a high concentration of low-density lipoprotein cholesterol (LDL-C) in the blood. However, the level may significantly vary between the two mentioned types of FH, and it is decidedly higher in HoFH. A chronically elevated concentration of LDL-C in the plasma leads to the occurrence of certain abnormalities, such as xanthomas in the tendons and skin, as well as corneal arcus. Nevertheless, a significantly more severe phenomenon is leading to the premature onset of cardiovascular disease (CVD) and its clinical implications, such as cardiac events, stroke or vascular dementia, even at a relatively young age. Due to the danger posed by this medical condition, we have investigated how both non-pharmacological and selected pharmacological treatment impact the course of FH, thereby reducing or postponing the risk of clinical manifestations of CVD. The primary objective of this review is to provide a comprehensive summary of the current understanding of FH, the effectiveness of lipid-lowering therapy in FH and to explain the anatomopathological correlation between FH and premature CVD development, with its complications. Full article

Evinacumab, a human monoclonal antibody against angiopoietin-like protein 3 (ANGPTL3), has recently been approved by the U.S. Food and Drug Administration as an add-on therapy for homozygous familial hypercholesterolemia (HoFH) in patients of 12 years and older. Its role as a triglyceride-lowering drug is also emerging in the literature. However, it has not been approved for this indication yet, neither in the adult nor in the pediatric population. We describe the case of a 10-year-old boy who underwent an allogeneic hematopoietic stem cell transplant for acute lymphoblastic leukemia complicated by chronic graft-versus-host disease (GVHD) and presented life-threatening refractory hypertriglyceridemia due to the concomitant use of ruxolitinib and sirolimus. After the failure of the insulin treatment and due to the technical impossibility of performing lipid apheresis, the child underwent evinacumab treatment, obtaining a dramatic rapid reduction in triglyceride and cholesterol levels. This is the first report of a pediatric patient younger than 12 years in Europe receiving evinacumab to treat severe hypertriglyceridemia. The therapy with angiopoietin-like proteins inhibitors has been effective, safe, and well-tolerated in our patient, suggesting that evinacumab may be used in the pediatric population when other therapeutic strategies are ineffective or contraindicated. Full article

Familial hypercholesterolemia (FH) is a hereditary disorder that causes severely elevated low-density lipoprotein (LDL-C) levels, which leads to an increased risk for premature cardiovascular disease. A variety of genetic variants can cause FH, namely variants in the genes for the LDL receptor (LDLR), apolipoprotein B (APOB), proprotein convertase subtilisin/kexin type 9 (PCSK9), and/or LDL-receptor adaptor protein 1 (LDLRAP1). Variants can exist in a heterozygous form (HeFH) or the more severe homozygous form (HoFH). If affected individuals are diagnosed early (through screening), they benefit tremendously from early initiation of lipid-lowering therapy, such as statins, and cardiovascular imaging to detect possible atherosclerosis. Over the last years, due to intensive research on the genetic basis of LDL-C metabolism, novel, promising therapies have been developed to reduce LDL-C levels and subsequently reduce cardiovascular risk. Results from studies on therapies focused on inhibiting PCSK9, a protein responsible for degradation of the LDLR, are impressive. As the effect of PCSK9 inhibitors (PCSK9-i) is dependent of residual LDLR activity, this medication is less potent in patients without functional LDLR (e.g., null/null variant). Novel therapies that are expected to become available in the near future focused on inhibition of another major regulatory protein in lipid metabolism (angiopoietin-like 3 (ANGPTL3)) might dramatically reduce the frequency of apheresis in children with HoFH, independently of their residual LDLR. At present, another independent risk factor for premature cardiovascular disease, elevated levels of lipoprotein(a) (Lp(a)), cannot be effectively treated with medication. Further understanding of the genetic basis of Lp(a) metabolism, however, offers a possibility for the development of novel therapies. Full article

Emerging studies in the literature describe an association between high-fat, low-carbohydrate diets and severe hypercholesterolemia consistent with the levels observed in patients with (homozygous) familial hypercholesterolemia (FH). High levels of low-density lipoprotein cholesterol (LDL-C) may result from the reduced clearance of LDL particles from the circulation, the increased production of their precursor, or a combination of both. The increased intake of (saturated) fat and cholesterol, combined with limited to no intake of carbohydrates and fiber, are the main features of diets linked to hypercholesterolemia. However, several observations in previous studies, together with our observations from our lipid clinic, do not provide a definitive pathophysiological explanation for severe hypercholesterolemia. Therefore, we review these findings and possible pathophysiological explanations as well as opportunities for future research. Altogether, clinicians should rule out high-fat, low-carbohydrate diets as a possible cause for hypercholesterolemia in patients presenting with clinical FH in whom no mutation is found and discuss dietary modifications to durably reduce LDL-C levels and cardiovascular disease risk. Full article

Genetics of Familial Hypercholesterolemia (FH) is ascribable to pathogenic variants in genes encoding proteins leading to an impaired LDL uptake by the LDL receptor (LDLR). Two forms of the disease are possible, heterozygous (HeFH) and homozygous (HoFH), caused by one or two pathogenic variants, respectively, in the three main genes that are responsible for the autosomal dominant disease: LDLR, APOB and PCSK9 genes. The HeFH is the most common genetic disease in humans, being the prevalence about 1:300. Variants in the LDLRAP1 gene causes FH with a recessive inheritance and a specific APOE variant was described as causative of FH, contributing to increase FH genetic heterogeneity. In addition, variants in genes causing other dyslipidemias showing phenotypes overlapping with FH may mimic FH in patients without causative variants (FH-phenocopies; ABCG5, ABCG8, CYP27A1 and LIPA genes) or act as phenotype modifiers in patients with a pathogenic variant in a causative gene. The presence of several common variants was also considered a genetic basis of FH and several polygenic risk scores (PRS) have been described. The presence of a variant in modifier genes or high PRS in HeFH further exacerbates the phenotype, partially justifying its variability among patients. This review aims to report the updates on the genetic and molecular bases of FH with their implication for molecular diagnosis. Full article

Familial hypercholesterolemia (FH) is the most common genetic disorder associated with premature atherosclerotic cardiovascular (CV) disease (ASCVD). However, it still is severely underdiagnosed. Initiating lipid-lowering therapy (LLT) in FH patients early in life can substantially reduce their ASCVD risk. As a result, identifying FH is of the utmost importance. The increasing availability of genetic testing may be useful in this regard. We aimed to evaluate the genetic profiles, clinical characteristics, and gender differences between the first consecutive patients referred for genetic testing with FH clinical suspicion in our institution (a Spanish cohort). Clinical information was reviewed, and all participants were sequenced for the main known genes related to FH: LDLR, APOB, PCSK9 (heterozygous FH), LDLRAP1 (autosomal recessive FH), and two other genes related to hyperlipidaemia (APOE and LIPA). The genetic yield was 32%. Their highest recorded LDLc levels were 294 ± 65 SD mg. However, most patients (79%) were under > 1 LLT medication, and their last mean LDLc levels were 135 ± 51 SD. LDLR c.2389+4A>G was one of the most frequent pathogenic/likely pathogenic variants and its carriers had significantly worse LDLc highest recorded levels (348 ± 61 SD vs. 282 ± 60 SD mg/dL, p = 0.002). Moreover, we identified an homozygous carrier of the pathogenic variant LDLRAP1 c.207delC (autosomal recessive FH). Both clinical and genetic hypercholesterolemia diagnosis was significantly established earlier in men than in women (25 years old ± 15 SD vs. 35 years old ± 19 SD, p = 0.02; and 43 ± 17 SD vs. 54 ± 19 SD, p = 0.02, respectively). Other important CV risk factors were found in 44% of the cohort. The prevalence of family history of premature ASCVD was high, whereas personal history was exceptional. Our finding reaffirms the importance of early detection of FH to initiate primary prevention strategies from a young age. Genetic testing can be very useful. As it enables familial cascade genetic testing, early prevention strategies can be extended to all available relatives at concealed high CV risk. Full article

Homozygous familial hypercholesterolemia (HoFH) is a rare inborn-errors-of-metabolism disorder characterized by devastatingly elevated low-density lipoprotein cholesterol (LDL-C) and premature cardiovascular disease. The gold standard for screening and diagnosing HoFH is genetic testing. In China, it is expensive and is always recommended for the most likely HoFH subjects with aggressive LDL-C phenotype. However, the LDL-C levels of HoFH patients and a substantial proportion of heterozygous FH (HeFH) patients overlapped considerably. Here, we performed a cost-effective metabolomic profiling on genetically diagnosed HoFH (n = 69) and HeFH patients (n = 101) with overlapping LDL-C levels, aiming to discovery a unique metabolic pattern for screening homozygotes in patients with severe FH. We demonstrated a differential serum metabolome profile in HoFH patients compared to HeFH patients. Twenty-one metabolomic alterations showed independent capability in differentiating HoFH from severe HeFH. The combined model based on seven identified metabolites yielded a corrected diagnosis in 91.3% of HoFH cases with an area under the curve value of 0.939. Collectively, this study demonstrated that metabolomic profiling serves as a useful and economical approach to preselecting homozygotes in FH patients with severe hypercholesterolemia and may help clinicians to conduct selective genetic confirmation testing and familial cascade screening. Full article

Homozygous familial hypercholesterolemia (HoFH) is the rare form of familial hypercholesterolemia causing extremely high low-density lipoprotein cholesterol (LDL-C) levels, leading to atherosclerotic cardiovascular disease (ASCVD) in the first decades of life, if left untreated. Early diagnosis and effective lipid lowering therapy (LLT) are crucial for the prevention of early ASCVD in patients with HoFH. On-treatment LDL-C levels are the best predictor of survival. However, due to the absent or defective LDL-receptor activity, most individuals with HoFH are resistant to conventional LLT, that leads to LDL-C clearance by upregulating LDL-receptors. We are at the dawn of a new era of effective pharmacotherapies for HoFH patients, with new agents providing an LDL-receptor independent cholesterol reduction. In this context, the present review provides a summary of the currently available therapies and emerging therapeutic agents for the management of patients with HoFH, in light of recent evidence and guideline recommendations. Full article