Universal screening for familial hypercholesterolemia in 2 populations

Homozygous phytosterolemia and a literature review: A case report

BACKGROUND

Phytosterolemia, also known as sitosterolemia, is a rare autosomal recessive disease characterized by elevated plasma plant sterol levels and xanthomata, which is easily misdiagnosed as familial hypercholesterolemia. Patients with homozygous phytosterolemia often have severe clinical manifestations, with xanthomata in childhood and premature atherosclerosis. Our patient had a milder clinical phenotype.

CASE SUMMARY

This report describes a patient with homozygous phytosterolemia who presented with only elevated cholesterol and low-density lipoprotein cholesterol (LDL-C) without xanthomata, arteriosclerosis, or hematological abnormalities. Homozygous mutation of ABCG5 which encodes an ATP-binding cassette transporter, was detected by whole exome sequencing and diagnosed as phytosterolemia. Measurement of the patient's plasma plant sterol levels detected significant elevations in stigmasterol, rapeseed oil-derived plant sterol, and β-glutaminol levels. Ezetimibe was started and a low plant sterol diet was recommended. The patient's blood lipid profile was reexamined one month later and showed significant decreases in total cholesterol and LDL-C levels. Phytosterolemia has similar clinical features as familial hypercholesterolemia, is highly susceptible to misdiagnosis, and has a very low incidence, and therefore clinicians need to consider a genetic diagnosis of a definitively hyperlipidemic disorder when statin drugs fail to lower lipid levels.

CONCLUSION

Phytosterolemia is easily misdiagnosed as familial hypercholesterolaemia and can be treated by dietary modification and cholesterol absorption inhibitors to lower blood lipids.

Prevalence, genetic variants, and clinical implications of hypocholesterolemia in children

BACKGROUND AND AIMS

In contrast to extensively studied hypercholesterolemia, knowledge of hypocholesterolemia is limited. This study aims to assess the prevalence, clinical characteristics, and genetics of children and adolescents with hypocholesterolemia.

METHODS

This national prospective cross-sectional cohort study was part of Slovenia's universal opt-out cholesterol screening program. The first part assessed hypocholesterolemia prevalence among 3538 children aged 5 years, randomly selected at the mandatory check-up. The second part included analysis of demographic and clinical data and genetic testing of 71 individuals with suspected hypocholesterolemia (total cholesterol [TC] < 3.0 mmol/L [116.0 mg/dL]) referred to the Lipid Clinic of University Children's Hospital Ljubljana.

RESULTS

The prevalence of hypocholesterolemia among 3538 children was 2.66 % (95 % CI: 2.13-3.19 %). Among the 71 genetically tested individuals with suspected hypocholesterolemia, those with pathogenic variants had lower TC (2.58 ± 0.44 mmol/L vs. 2.85 ± 0.42 mmol/L [99.77 ± 17.02 mg/dL vs. 110.20 ± 16.24 mg/dL]; p = 0.037) and low-density lipoprotein cholesterol (1.00 ± 0.40 mmol/L vs. 1.33 ± 0.40 mmol/L [38.67 ± 15.47 mg/dL vs. 51.43 ± 15.47 mg/dL]; p = 0.014) compared to those without such variants. Genetic testing identified pathogenic alterations in 15 subjects, including 4 novel loss-of-function variants in the APOB gene. All but one subject were asymptomatic.

CONCLUSIONS

This study provides new clinical and genetic insights into hypocholesterolemia. Asymptomatic patients with hypocholesterolemia may not require further evaluation, but additional research is needed to understand hypocholesterolemia better.

Familial hypercholesterolemia in Chinese children and adolescents: a multicenter study

BACKGROUND

Familial hypercholesterolemia (FH) is an inherited disorder mainly marked by increased low-density lipoprotein cholesterol (LDL-C) concentrations and a heightened risk of early-onset arteriosclerotic cardiovascular disease (ASCVD). This study seeks to characterize the genetic spectrum and genotype‒phenotype correlations of FH in Chinese pediatric individuals.

METHODS

Data were gathered from individuals diagnosed with FH either clinically or genetically at multiple hospitals across mainland China from January 2016 to June 2024.

RESULTS

In total, 140 children and adolescents (mean age of 6.00 years) with clinically and genetically diagnosed FH were enrolled in the study, with 87 distinct variants identified in the LDLR, APOB and PCSK9 genes. Among the variants, 11 variants were newly identified worldwide, with 9 classified as "pathogenic" or "likely pathogenic", and 2 classified as "variants of uncertain significance". Additionally, the 5 most common variants in the study were c.1448G > A (p.W483*), c.1879G > A (p.A627T), c.1216C > A (p.R406R), and c.1747C > T (p.H583Y) in the LDLR gene, as well as c.10579C > T (p.R3527W) in the APOB gene, accounting for 49.29% (69/140) of all patients. These variants are primarily observed in the Asian or Chinese population and are distinct from those present in Caucasian groups. In this cohort, 105 patients were diagnosed with heterozygous FH (HeFH), while 35 were diagnosed with homozygous FH (HoFH). Finally, only 28.57% of the patients (40/140) were using lipid-lowering medications with 33.33% of HoFH patients initiating treatment after the age of 8. Additionally, only 3 compound heterozygous patients (2.14%) underwent liver transplantation because of significantly high lipid levels.

CONCLUSION

This study reveals the variable genotypes and phenotypes of children with FH in China and illustrates that the genotypes in the Chinese population differ from those in Caucasians, providing a valuable dataset for the clinical genetic screening of FH in China. Furthermore, the older age at diagnosis and treatment highlights the underdiagnosis and undertreatment of Chinese FH pediatric patients, suggesting that early identification should be improved through lipid or genetic screening, and that more timely and regular pharmacological treatments should be implemented.

Universal screening for familial hypercholesterolaemia: how can we maximise benefits and minimise potential harm for children and their families?

PURPOSE OF REVIEW

Universal Screening programmes to identify subjects with familial hypercholesterolaemia (FH) have been the subject of much recent interest. However, any screening programme can cause harm as well as having potential benefits. Here we review recent papers using different ages and strategies to identify subjects with FH, and examine to what extent the publications provide quantitative or qualitative evidence of benefit or harm to children and adults.

RECENT FINDINGS

Three studies have been published over the last 2 years where Universal Screening for FH has been carried out in infancy, at the time of routine vaccinations, or at preschool age. Next-generation sequencing of all known FH-causing genes has been used to determine the proportion of screened individuals, who have total or low-density lipoprotein cholesterol (LDL-C) concentrations above a predetermined threshold (such as >95th percentile), with genetically confirmed FH.

SUMMARY

While we fully support the concept of Universal Screening for FH, which appears feasible and of potential clinical utility at all of the different ages examined, there is little data to document potential benefit or how to mitigate potential harms. Future study protocols should include collection of such data to strengthen the case of roll out of Universal Screening programmes.

The Importance of Genetic Testing for Familial Hypercholesterolemia: A Pediatric Pilot Study

Background and Objectives: Familial hypercholesterolemia (FH) is a genetic disease that is massively underdiagnosed worldwide. Affected patients are at high risk of cardiovascular events at young ages. Early intervention in childhood could help prevent heart attacks and cerebral strokes in these patients. Materials and Methods: We conducted an interventional study including 10 patients that previously underwent genetic testing for familial hypercholesterolemia. These patients received lifestyle and diet recommendations that they followed for a year before being reevaluated. Results: Patients with negative genetic testing were able to achieve lower levels in their lipid panel values compared to the patients with positive genetic testing, with lifestyle changes alone. LDL-cholesterol levels decreased by 18.5% in patients without FH while patients genetically confirmed with FH failed to achieve lower LDL-cholesterol levels without medication. Conclusions: Genetic testing for FH is not always part of screening algorithms for FH. Some studies even advise against it. Our study proved the importance of genetic testing for FH when suspecting this disorder and choosing the treatment course for patients.

Overcoming the real and imagined barriers to cholesterol screening in pediatrics

Recent guidance by the United States Preventive Services Task Force has renewed the debate surrounding the benefits of pediatric lipid screening. This commentary reviews the evolution of the pediatric lipid screening recommendations in the United States, followed by an exploration of real and imagined challenges that prevent optimal cholesterol screening rates in children. Real challenges substantively prevent the uptake of these guidelines into practice; imagined challenges, such as identifying the best age to screen, are often context-dependent and can also be surmounted. Experiences from other countries identify potential facilitators to improving screening and additional barriers. Implementation science provides guidance on overcoming the real barriers, translating evidence-based recommendations into clinical practice, and informing the next wave of solutions to overcome these challenges.

Genetic testing for familial hypercholesterolemia

PURPOSE OF REVIEW

Despite familial hypercholesterolemia (FH) being the most common genetic cause of cardiovascular disease (CVD), genetic testing is rarely utilized in the US. This review summarizes what is known about the clinical utility of genetic testing and its role in the diagnosis and screening of FH.

RECENT FINDINGS

The presence of an FH-causative variant is associated with a substantially higher risk of CVD, even when low-density lipoprotein cholesterol (LDL-C) levels are only modestly elevated. Genetic testing can facilitate the identification of FH cases who may be missed by clinical diagnostic criteria, improve risk stratification beyond LDL-C and family history, guide treatment decisions, and improve treatment initiation and adherence. Genetic testing can be incorporated into FH screening and diagnosis algorithms, including cascade, targeted, and universal screening. Integrating genetic testing into cascade screening can enhance the effectiveness of the process. Several models of universal FH screening with coordinated genetic and lipid testing are feasible and effective.

SUMMARY

More systematic integration of genetic testing into FH diagnosis and screening can significantly reduce the burden of this condition through early detection and treatment. Further pragmatic implementation studies are needed to determine how to more effectively and affordably integrate genetic testing into clinical lipid screening programs.

Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study

BACKGROUND

Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies.

METHODS

For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia.

FINDINGS

Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8-13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05-6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50-75% of children and adolescents with familial hypercholesterolaemia not being identified.

INTERPRETATION

Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life.

FUNDING

Pfizer, Amgen, Merck Sharp & Dohme, Sanofi-Aventis, Daiichi Sankyo, and Regeneron.

Childhood Screening for Familial Hypercholesterolemia: JACC Review Topic of the Week

Screening for familial hypercholesterolemia (FH) in childhood remains controversial. Existing guidelines offer practitioners conflicting advice despite generally agreeing on the evidence and areas in which evidence is lacking, including a lack of long-term clinical trials demonstrating coronary event reduction as a result of screening and long-term data on statin side effects. A limitation of existing evidence-based frameworks is reliance on 1 evidence grading system to determine recommendations. However, rigorous evidence evaluation alternatives relevant to FH exist. FH is considered a tier 1 genetic condition, meaning that identification and treatment will improve health outcomes among those affected. Elevated low-density lipoprotein cholesterol, the primary consequence of FH, can be considered causal for atherosclerosis and coronary heart disease. Incorporating these concepts into existing evidence pathways allows the inclusion of surrogate clinical trial outcomes (low-density lipoprotein cholesterol reduction and atherosclerosis regression) and observational data on medication safety, strengthening the evidence for pediatric screening for FH.

Barriers and shortcomings in access to cardiovascular management and prevention for familial hypercholesterolemia during the COVID-19 pandemic

Familial hypercholesterolemia (FH) is a hereditary condition caused by mutations in the lipid pathway. The goal in managing FH is to reduce circulating low-density lipoprotein cholesterol and, therefore, reduce the risk of developing atherosclerotic cardiovascular disease (ASCVD). Because FH patients were considered high risk groups due to an increased susceptible for contracting COVID-19 infection, we hypothesized whether the effects of the pandemic hindered access to cardiovascular care. In this review, we conducted a literature search in databases Pubmed/Medline and ScienceDirect. We included a comprehensive analysis of findings from articles in English related and summarized the effects of the pandemic on cardiovascular care through direct and indirect effects. During the COVID-19 pandemic, FH patients presented with worse outcomes and prognosis, especially those that have suffered from early ASCVD. This caused avoidance in seeking care due to fear of transmission. The pandemic severely impacted consultations with lipidologists and cardiologists, causing a decline in lipid profile evaluations. Low socioeconomic communities and ethnic minorities were hit the hardest with job displacements and lacked healthcare coverage respectively, leading to treatment nonadherence. Lock-down restrictions promoted sedentary lifestyles and intake of fatty meals, but it is unclear whether these factors attenuated cardiovascular risk in FH. To prevent early atherogenesis in FH patients, universal screening programs, telemedicine, and lifestyle interventions are important recommendations that could improve outcomes in FH patients. However, the need to research in depth on the disproportionate impact within different subgroups should be the forefront of FH research.

Non-alcoholic fatty liver disease in a pediatric patient with heterozygous familial hypobetalipoproteinemia due to a novel APOB variant: a case report and systematic literature review

Background

Familial hypobetalipoproteinemia (FHBL) is an autosomal semi-dominant disorder usually caused by variants in the APOB gene that frequently interferes with protein length. Clinical manifestations include malabsorption, non-alcoholic fatty liver disease, low levels of lipid-soluble vitamins, and neurological, endocrine, and hematological dysfunction.

Methods

Genomic DNA was isolated from the blood samples of the pediatric patient with hypocholesterolemia and his parents and brother. Next-generation sequencing (NGS) was performed, and an expanded dyslipidemia panel was employed for genetic analysis. In addition, a systematic review of the literature on FHBL heterozygous patients was performed.

Case report

Genetic investigation revealed the presence of a heterozygous variant in the APOB (NM_000384.3) gene c.6624dup[=], which changes the open reading frame and leads to early termination of translation into the p.Leu2209IlefsTer5 protein (NP_000375.3). The identified variant was not previously reported. Familial segregation analysis confirmed the variant in the mother of the subject, who also has a low level of low-density lipoprotein and non-alcoholic fatty liver disease. We have introduced therapy that includes limiting fats in the diet and adding lipid-soluble vitamins E, A, K, and D and calcium carbonate. We reported 35 individuals with APOB gene variations linked to FHBL in the systematic review.

Conclusion

We have identified a novel pathogenic variant in the APOB gene causing FHBL in pediatric patients with hypocholesterolemia and fatty liver disease. This case illustrates the importance of genetic testing for dyslipidemias in patients with significant decreases in plasma cholesterol as we can avoid damaging neurological and ophthalmological effects by sufficient vitamin supplementation and regular follow-ups.

Mapping of familial hypercholesterolemia and dyslipidemias basic management infrastructure in Pakistan: a cross-sectional study

BACKGROUND

Familial hypercholesterolemia (FH) is an autosomal inherited disorder characterised by elevated low-density lipoprotein cholesterol and premature cardiovascular events. Despite being declared as a public health priority, FH remains highly underdiagnosed, generally due to the lack of awareness and shortcomings in the available infrastructure, particularly in lower income countries.

METHODS

To map the existing infrastructure for the management of FH, a survey was conducted among 128 physicians (cardiologists, paediatricians, endocrinologists, and internal medicine specialists) from different regions of Pakistan.

FINDINGS

The respondents encountered a limited number of adults or children with diagnosed FH. A very small proportion of the population had access to free cholesterol and genetic testing even when indicated by a physician. In general, cascade screening of the relatives was not performed. Uniform diagnostic criteria for FH had not been established even within the same institution or province. The use of statins and ezetimibe in addition to lifestyle changes were the most common recommended treatment option for FH patients. The respondents considered lack of financial resources as a major barrier for the management of FH and stressed on taking relevant measures for a uniform FH screening programs around the country.

INTERPRETATION

National FH screening programmes are not in place worldwide hence FH is commonly undiagnosed, and many individuals are at a high risk for cardiovascular diseases. Timely screening of population for FH requires knowledge about FH among the clinicians and the availability of fundamental infrastructure coupled with sufficient financial resources.

FUNDING

The authors confirm independence from the sponsor. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results. FS received funding from Higher Education Commission, Pakistan (Grant 20-15760) and UG received grants from Slovenian Research Agency (J3-2536, P3-0343).

Evaluation of Body Mass Index, Overweight and Obesity Status, and Cholesterol Levels in Younger Children

This cohort study examines cholesterol levels in children with overweight or obesity.

How Genetic Variants in Children with Familial Hypercholesterolemia Not Only Guide Detection, but Also Treatment

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.

Paediatric familial hypercholesterolaemia screening in Europe: public policy background and recommendations

Familial hypercholesterolaemia (FH) is under-recognized and under-treated in Europe leading to significantly higher risk for premature heart disease in those affected. As treatment beginning early in life is highly effective in preventing heart disease and cost-effective in these patients, screening for FH is crucial. It has therefore now been recognized by the European Commission Public Health Best Practice Portal as an effective strategy. Model programmes exist in Europe to identify young individuals with FH, which are based on cascade screening of first-degree relatives of affected individuals, universal screening for high cholesterol, opportunistic screening of high-risk individuals, or a combination of the above approaches. Recommendations presented herein to improve identification of FH emphasize that every country should have an FH screening programme. These programmes should be adapted from existing strategies to best fit the individual country's healthcare system, governments should provide financial support for these programmes and related care, and further research to optimize care and implementations should be conducted.

Screening for familial hypercholesterolaemia in primary school children: protocol for a cross-sectional, feasibility study in Luxembourg city (EARLIE)

INTRODUCTION

Familial hypercholesterolaemia (FH) is a frequent (1:300) autosomal dominantly inherited condition which causes premature (women <60 years, men <55 years) cardio-cerebrovascular disease (CVD). Early detection and initiation of treatment can prevent the development of CVD and premature death. Our pilot study aims to investigate the prevalence of FH, the feasibility and efficacy of a screening based on a capillary blood test performed during a school medicine visit in primary school children.

METHODS AND ANALYSIS

In this cross-sectional study, all children (n=3200) between 7 and 12 years, attending primary school in the city of Luxembourg and invited for their mandatory medical school examinations between 2021 and 2023 are invited to participate. A study nurse performs a capillary blood test to analyse the lipid profile. Families receive the result including an interpretation and invitation to seek medical advice if indicated. If FH is confirmed, a reverse cascade screening in that family will be proposed. The child will receive standard care. Primary outcome is the occurrence of confirmed FH in the study population. Secondary outcomes include the percentage of children screened, percentage of children with abnormal lipid values, percentage of families screened and percentage of families with additionally identified members suffering from hypercholesterolaemia. A health economic analysis will be performed.

ETHICS AND DISSEMINATION

Ethics approval (reference number 202108/01) has been obtained from the National Research Ethics Committee (CNER (Luxembourg)) and was authorised by the ministry of health in Luxembourg. Families receive written information with an informed consent form. Participation requires an informed consent form signed by the parents. The results will be disseminated in peer-reviewed publications, conference presentations and by public media to the general public.

TRIAL REGISTRATION NUMBER

NCT05271305.