Testing For Familial Hypercholesterolemia Research Articles

IMPACT-FH Study for Implementing Innovative Family Communication and Cascade Testing Strategies for Familial Hypercholesterolemia

BackgroundRelatives of probands diagnosed with familial hypercholesterolemia (FH) should undergo cascade testing for FH. ObjectivesThe purpose of this study was to evaluate probands’ choices of innovative strategies to communicate their FH result with relatives and facilitate cascade testing uptake. MethodsProbands with an FH genetic result from the MyCode Community Health Initiative could choose to share their FH result with adult blood relatives via the Family and Healthcare Professional Packet (packet), family sharing and cascade chatbots (chatbot), and/or FH Outreach and Support Program (direct contact). Cascade testing uptake was measured as reported completion of genetic or cholesterol testing. Generalized estimating equations models were used to identify factors associated with testing. ResultsOne hundred seventy five probands received an FH result, median age was 58.9 (IQR: 44.9-69.3), and 58.9% were female. Probands shared information about 1,915 adult and 163 minor relatives (11.9 relatives per proband). Seventy percent of probands (121/175) selected at least one strategy for at least one adult relative. An average of 1.2 strategies was selected per adult relative. Cascade testing was completed for 26.6% (144/541) of adults with at least one strategy selected, 2.4% (33/1,374) of adults without a strategy selected, and 25.2% (41/163) of minor relatives. Factors associated with increased cascade testing uptake were selection of at least one strategy (6.32 higher odds), specifically, selection of direct contact (16.78 higher odds). ConclusionsStrategies implemented improved FH cascade testing uptake compared to previous estimates and in families where no strategy was selected. Overall uptake remains insufficient, which can be attributed to probands reluctance to select a strategy for many relatives.

Opportunistic Detection of Phytosterolaemia during Genetic Testing for FH: Case Series and Contextual Review.

Homozygous phytosterolaemia, is a rare autosomal recessive disorder which lead to severely elevated plasma levels of plant phytosterols causing an increased risk of coronary artery disease (CAD) and mimics the clinical presentation of familial hypercholesterolaemia(FH). Integration of the genetic variants for homozygous phytosterolaemia into the genetic panel for FH in clinical practice likely increases the detection of milder genetic forms of phytosterolaemia, of which the implications to clinical practice including cascade testing remain unclear. We report three families with pathogenic loss-of-function variants in ABCG5 and/or ABCG8, in which probands were identified incidentally when genetically testing them for FH. The proband of the first family was a 35-year-old man with a homozygous ABCG5 loss-of-function variant (c.1336C > T, p.Arg446*) causing severe phytosterolaemia and premature CAD on cardiac imaging; his younger brother was heterozygous for the same variant with mildly elevated phytosterol levels. The second family included 2 sisters (31 and 29-year-old) with digenic variants in ABCG5 (c.1336C > T, p.Arg446*) and ABCG8 (c.1269G > T, p.Glu423Asp with uncertain significance) with moderately elevated plasma phytosterol levels and premature CAD on cardiac imaging. The third family referred to a 68-year-old man and his 44-year-old daughter who were both heterozygous for a pathogenic ABCG5 variant (c.1166G > A, p.Arg389His), had mild phytosterolaemia and CAD on cardiac imaging. Treatment with ezetimibe alone or in combination with colesevelam reduced elevated plasma sitosterol and campesterol concentrations by 30 to 80%. Phytosterolaemia is specific genetic disorder that can mimic FH, cause premature atherosclerosis, and require specific pharmacotherapy. Cascade testing for pathogenic ABCG5/G8 variants can lead to earlier detection and treatment of affected family members.

Expanded genetic testing in familial hypercholesterolemia—A single center's experience

ObjectiveAssess the yield of genetic testing for pathogenic variants in ABCG5, ABCG8, LIPA, and APOE in individuals with personal and family histories suggestive of familial hypercholesterolemia. MethodsRetrospective review of patients seen in the Advanced Lipid Disorders Clinic at Johns Hopkins ResultsIn the lipid clinic at a single center during the years 2015–2023, 607 patients underwent genetic testing for familial hypercholesterolemia, of which 263 underwent the expanded genetic testing for sitosterolemia. Eighty-eight patients had genetic testing which included APOE, and 22 patients had testing which included LIPA. Among these, one patient was identified to have a pathogenic variant in APOE and another patient with a pathogenic variant in ABCG5 (0.7 % yield). The frequency of a positive result was double that of a variant of uncertain significance. ConclusionThese data suggest in rare cases expanded testing can provide answers for patients and families with a minimal likelihood of a variant of uncertain significance.

The diagnostic value of genetic testing in familial hypercholesterolemia in patients with premature myocardial infarction

Objective: To evaluate the diagnostic value of gene testing in familial hypercholesterolemia (FH) in patients with premature myocardial infarction(PMI). Methods: This study was a single center cross-sectional study. A retrospective analysis was made on PMI patients who visited the People's Hospital of Peking University from May 1, 2015 to March 31, 2017. Clinical data of patients was collected and gene testing of FH related genes low density lipoprotein receptor (LDLR), proprotein convertase subtilisin/kexin type 9 (PCSK9), apolipoprotein B(APOB) and low density lipoprotein receptor adaptor protein 1(LDLRAP1) was carried out. Clinical diagnosis of FH patients was performed using Simon Broome criteria, DLCN criteria, and FH Chinese expert consensus. Results: There were 188 males (83.6%) among 225 PMI patients, and the age of the first myocardial infarction was (46.6±7.2) years old. Ten patients carried FH pathogenic or possibly pathogenic mutations (4.4%). Compared with Simon Broome standard, DLCN standard and FH Chinese expert consensus, gene testing increased the diagnostic rate of FH by 53.3%, 33.3% and 42.1% respectively. Conclusion: Gene testing is helpful to improve the diagnosis of FH, and it is important to start the standard treatment of FH as early as possible in patients with premature myocardial infarction.

Genetic Counseling and Genetic Testing for Familial Hypercholesterolemia.

Familial hypercholesterolemia (FH) is one of the most common autosomal codominant Mendelian diseases. The major complications of FH include tendon and cutaneous xanthomas and coronary artery disease (CAD) associated with a substantial elevation of serum low-density lipoprotein levels (LDL). Genetic counseling and genetic testing for FH is useful for its diagnosis, risk stratification, and motivation for further LDL-lowering treatments. In this study, we summarize the epidemiology of FH based on numerous genetic studies, including its pathogenic variants, genotype-phenotype correlation, prognostic factors, screening, and usefulness of genetic counseling and genetic testing. Due to the variety of treatments available for this common Mendelian disease, genetic counseling and genetic testing for FH should be implemented in daily clinical practice.

The Lipoprotein Profile Evaluated by 1H-NMR Improves the Performance of Genetic Testing in Familial Hypercholesterolemia.

The familial hypercholesterolemia (FH) diagnosis is based on clinical and genetic criteria. A relevant proportion of FH patients fulfilling the criteria for definite FH have negative genetic testing. Increasing the identification of true genetic-based FH is a clinical challenge. Deepening the analysis of lipoprotein alterations could help increase the yield of genetic testing. We evaluated whether the number, size, and composition of lipoproteins assessed by 1H-NMR could increase the identification of FH patients with pathogenic gene variants. We studied 294 clinically definite FH patients, 222 (75.5%) with positive genetic testing, as the discovery cohort. As an external validation cohort, we studied 88 children with FH, 72 (81%) with positive genetic testing. The advanced lipoprotein test based on 1H-NMR (Liposcale®) was performed at baseline after a lipid-lowering drug wash-out of at least 6 weeks. The association of variables with genetic variants was evaluated by random forest and logistic regression. Areas under the curve (AUCs) were calculated. A predictive formula was developed and applied to the validation cohort. A formula derived from NMR lipoprotein analyses improved the identification of genetically positive FH patients beyond LDL-C levels (AUC=0.87). The parameters contributing the most to the identification formula were LDL particle number, HDL size and remnant cholesterol. The formula also increases the classification of FH children with a pathogenic genetic variation. NMR lipoprotein profile analysis identifies differences beyond standard lipid parameters that help identify FH with a positive pathogenic gene variant, increasing the yield of genetic testing in FH patients.

Genetic testing for familial hypercholesterolemia in a Finnish cohort of patients with premature coronary artery disease and elevated LDL-C levels.

Based on Finnish LDLR-founder variations, the prevalence of familial hypercholesterolemia (FH) in Finland is estimated to be at least 1:600. Patients with FH have increased risk of premature coronary artery disease (CAD) and thus the prevalence of FH is expected to be higher in this subgroup. To assess the prevalence of monogenic FH in a Finnish cohort of patients with premature CAD and elevated low-density lipoprotein cholesterol (LDL-C) levels. Among 28,295 patients undergoing angiography at Heart Hospital at Tampere University Hospital between 2007 and 2017, we identified 162 patients diagnosed with premature CAD (men aged <55 years and women aged <60 years) and history of high LDL-C (≥5 mmol/L) levels without secondary causes of hypercholesterolemia. Clinical probability of FH was estimated, and genetic testing of FH was carried out in 80 patients with informed consent. Of the 80 patients with premature CAD and history of high LDL-C levels, 70% were men; the age at diagnosis of CAD for male and female patients was 48 and 53 years, respectively. In total, 58 (73%) patients had probable (n = 54) or definite (n = 4) FH based on Dutch Lipid Clinic Network criteria. A pathogenic variant of FH was found in five (6%) patients. Prevalence of the genetically verified FH was 1:16. The FH variant was found in 75% of patients with definite FH. The prevalence of genetically verified FH was 1:16 among patients with premature CAD and elevated LDL-C level, which is 38 times higher than the estimated prevalence of 1:600 in the general Finnish population.

Genetic Spectrum and Cascade Screening of Familial Hypercholesterolemia in Routine Clinical Setting in Hong Kong.

Familial hypercholesterolemia (FH) is a prevalent but often underdiagnosed monogenic disorder affecting lipoprotein metabolism, and genetic testing for FH has not been widely conducted in Asia in the past. In this cross-sectional study of 31 probands (19 adults and 12 children) and an addition of 15 individuals (12 adults and 3 children), who underwent genetic testing and cascade screening for FH, respectively, during the period between February 2015 and July 2023, we identified a total of 25 distinct LDLR variants in 71.0% unrelated probands. Among the adult proband cohort, a higher proportion of genetically confirmed cases exhibited a positive family history of premature cardiovascular disease. Treatment intensity required to achieve an approximate 50% reduction in pretreatment low-density lipoprotein cholesterol (LDL-C) exhibited potentially better diagnostic performance compared to pretreatment LDL-C levels, Dutch Lipid Clinic Network Diagnostic Criteria (DLCNC) score, and modified DLCNC score. Adult individuals identified through cascade screening demonstrated less severe phenotypes, and fewer of them met previously proposed local criteria for FH genetic testing compared to the probands, indicating that cascade screening played a crucial role in the early detection of new cases that might otherwise have gone undiagnosed. These findings underscore the significance of genetic testing and cascade screening in the accurate identification and management of FH cases.

Low-Cost High-Throughput Genotyping for Diagnosing Familial Hypercholesterolemia.

Familial hypercholesterolemia (FH) is a common but underdiagnosed genetic disorder characterized by high low-density lipoprotein cholesterol levels and premature cardiovascular disease. Current sequencing methods to diagnose FH are expensive and time-consuming. In this study, we evaluated the accuracy of a low-cost, high-throughput genotyping array for diagnosing FH. An Illumina Global Screening Array was customized to include probes for 636 variants, previously classified as FH-causing variants. First, its theoretical coverage was assessed in all FH variant carriers diagnosed through next-generation sequencing between 2016 and 2022 in the Netherlands (n=1772). Next, the performance of the array was validated in another sample of FH variant carriers previously identified in the Dutch FH cascade screening program (n=1268). The theoretical coverage of the array for FH-causing variants was 91.3%. Validation of the array was assessed in a sample of 1268 carriers of whom 1015 carried a variant in LDLR, 250 in APOB, and 3 in PCSK9. The overall sensitivity was 94.7% and increased to 98.2% after excluding participants with variants not included in the array design. Copy number variation analysis yielded a 89.4% sensitivity. In 18 carriers, the array identified a total of 19 additional FH-causing variants. Subsequent DNA analysis confirmed 5 of the additionally identified variants, yielding a false-positive result in 16 subjects (1.3%). The FH genotyping array is a promising tool for genetically diagnosing FH at low costs and has the potential to greatly increase accessibility to genetic testing for FH. Continuous customization of the array will further improve its performance.

Possible explanations for the common clinical familial hypercholesterolemia phenotypes in the Faroe Islands

The prevalence of clinical familial hypercholesterolemia (FH) is very high in the Faroe Islands, but the possible causes are unknown. We aimed to describe potential genetic causes of FH in the Faroe Islands and to investigate whether levels of lipoprotein(a) and measures of dietary habits were associated with clinical FH in the Faroe Islands. In this case-control study, we identified potential clinical FH cases aged 18-75 years registered within a nationwide clinical laboratory database in the Faroe Islands and invited them for diagnostic evaluation according to clinical FH scoring systems. Controls were identified in the background population. Lipoprotein(a) was measured in plasma, while the fatty acid composition was determined in adipose tissue. The habitual diet of the participants was assessed using a food frequency questionnaire. Genetic testing for FH and polygenic variants was performed in a selection of clinical FH cases. A total of 121 clinical FH cases and 123 age- and sex-matched controls were recruited. We found a very low frequency of monogenic FH (2.5%), but a high level of polygenic FH (63%) in those genetically tested (67%). High levels of plasma lipoprotein(a) were associated with high odds of clinical FH. Clinical FH cases had a lower intake of saturated fatty acids (SFAs) measured by a high fat-score and a lower content of SFAs in adipose tissue compared with controls. The high prevalence of FH in the Faroe Islands may be due to polygenic causes of hypercholesterolemia and to a lesser extent other genetic factors and elevated plasma lipoprotein(a) levels.

Genetic Testing for Familial Hypercholesterolemia in a Pediatric Group: A Romanian Showcase.

Familial hypercholesterolemia (FH) is a genetic disease marked by high levels of LDL-cholesterol. This condition has long-term clinical implications, such as cardiovascular events, that are evident during adult life. Here, we report on a single-center cross-sectional showcase study of genetic testing for FH in a Romanian pediatric group. Genetic testing for FH was performed on 20 Romanian pediatric patients, 10 boys and 10 girls, admitted with LDL-cholesterol levels over 130 mg/mL to the National Institute for Mother and Child Health "Alesssandrescu-Rusescu" in 2020. Genetic testing was performed using the Illumina TruSight Cardio panel. We identified pathogenic/likely pathogenic variants that could explain the phenotype in 5/20 cases. The involved genes were LDLR and APOB. Clinical signs that suggest the diagnosis of FH are scarce for the pediatric patient, although it can be diagnosed early during childhood by lipid panel screening. Prevention could prove lifesaving for some of these patients.

Genetic testing increases the likelihood of a diagnosis of familial hypercholesterolaemia among people referred to lipid clinics: Danish national study

Background and aimsIt is unclear to what extent genetic testing improves the ability to diagnose familial hypercholesterolaemia (FH). We investigated the percentage with FH among individuals referred to Danish lipid clinics, and evaluated the impact of genetic testing for a diagnosis of FH. MethodsFrom September 2020 through November 2021, all patients referred for possible FH to one of the 15 Danish lipid clinics were invited for study participation and >97% (n = 1488) accepted. The Dutch Lipid Clinical Network criteria were used to diagnose clinical FH. The decision of genetic testing for FH was based on local practice. ResultsA total of 1243 individuals were referred, of whom 25.9% were diagnosed with genetic and/or clinical FH. In individuals genetically tested (n = 705), 21.7% had probable or definite clinical FH before testing, a percentage that increased to 36.9% after genetic testing. In individuals with unlikely and possible FH before genetic testing, 24.4% and 19.0%, respectively, had a causative pathogenic variant. ConclusionsIn a Danish nationwide study, genetic testing increased a diagnosis of FH from 22% to 37% in patients referred with hypercholesterolaemia suspected of having FH. Importantly, approximately 20% with unlikely or possible FH, who without genetic testing would not have been considered having FH (and family screening would not have been undertaken), had a pathogenic FH variant. We therefore recommend a more widespread use of genetic testing for evaluation of a possible FH diagnosis and potential cascade screening.

Opportunistic Genetic Screening for Familial Hypercholesterolemia in Heart Transplant Patients.

Heart transplantation remains the gold standard for the treatment of advanced heart failure (HF). Identification of the etiology of HF is mandatory, as the specific pathology can determine subsequent treatment. Early identification of familial hypercholesterolemia (FH), the most common genetic disorder associated with premature cardiovascular disease, has a potential important impact on clinical management and public health. We evaluated the genetic information in the genes associated with FH in a cohort of 140 heart-transplanted patients. All patients underwent NGS genetic testing including LDLR, APOB, and PCSK9. We identified four carriers of rare pathogenic variants in LDLR and APOB. Although all four identified carriers had dyslipidemia, only the one carrying the pathogenic variant LDLR c.676T>C was transplanted due to CAD. Another patient with heart valvular disease was carrier of the controversial LDLR c.2096C>T. Two additional patients with non-ischemic dilated cardiomyopathy were carriers of variants in APOB (c.4672A>G and c.5600G>A). In our cohort, we identified the genetic cause of FH in patients that otherwise would not have been diagnosed. Opportunistic genetic testing for FH provides important information to perform personalized medicine and risk stratification not only for patients but also for relatives at concealed high cardiovascular risk. Including the LDLR gene in standard NGS cardiovascular diagnostics panels should be considered.

Use of Lipoprotein(a) to improve diagnosis and management in clinical familial hypercholesterolemia

Background and aimsLipoprotein(a) (Lp(a)) is an LDL-like particle whose plasma levels are largely genetically determined. The impact of measuring Lp(a) in patients with clinical familial hypercholesterolemia (FH) referred for genetic testing is largely unknown. We set out to evaluate the contribution of (genetically estimated) Lp(a) in a large nation-wide referral population of clinical FH. MethodsIn 1504 patients referred for FH genotyping, we used an LPA genetic instrument (rs10455872 and rs3798220) as a proxy for plasma Lp(a) levels. The genetic Lp(a) proxy was used to correct LDL-cholesterol and reclassify patients with clinical FH based on Dutch Lipid Criteria Network (DLCN) scoring. Finally, we used estimated Lp(a) levels to reclassify ASCVD risk using the SCORE and SMART risk scores. ResultsLPA SNPs were more prevalent among mutation-negative compared with mutation-positive patients (296/1280 (23.1%) vs 35/224 (15.6%), p = 0.016). Among patients with genetically defined high Lp(a) levels, 9% were reclassified to the DLCN category ‘unlikely FH’ using Lp(a)-corrected LDL-cholesterol (LDL-Ccor) and all but one of these patients indeed carried no FH variant. Furthermore, elevated Lp(a) reclassified predicted ASCVD risk into a higher category in up to 18% of patients. ConclusionsIn patients referred for FH molecular testing, we show that taking into account (genetically estimated) Lp(a) levels not only results in reclassification of probability of genetic FH, but also has an impact on individual cardiovascular risk evaluation. However, to avoid missing the diagnosis of an FH variant, clear thresholds for the use of Lp(a)-cholesterol adjusted LDL-cholesterol levels in patients referred for genetic testing of FH must be established.

*Ketogenic Diets Exacerbating Hypercholesterolemia in APOE Variants and APOB Mutations-Potential Role for Measuring Intestinal Absorption of Lipids

Lead Author's Financial Disclosures Nothing to disclose. Study Funding None. Background/Synopsis Familial Hypercholesterolemia (FH) is caused primarily by mutations in either LDL receptor, APOB, or PCSK9 genes. There are other genetic causes of LDL elevation including APOE4 variants. Objective/Purpose We present two patients with markedly elevated LDL suspicious for FH who were subsequently diagnosed with APOE3/4 variants while on ketogenic diets. We also present a patient with a known APOB mutation who had a marked elevation of LDL on a ketogenic diet. Methods Case 1: 58-year-old male with no prior medical history was found to have elevated cholesterol of 600mg/dL and LDL>455mg/dL while on a ketogenic diet. Prior to initiating the diet, his cholesterol was 206mg/dL and LDL was 132mg/dL. Genetic testing revealed a ApoE3/4 variant. His most recent cholesterol increased to 706mg/dL and LDL to >500mg/dL. Case 2: 53-year-old male with hypertension cholesterol of 282mg/dL and LDL of 212mg/dL went on a ketogenic diet and lost 100lbs. Follow up lipid panel demonstrated a cholesterol of 400mg/dL and LDL of 317mg/dL. Genetic testing revealed a APOE3/4 variant. Case 3: 45-year-old female with FH and known APOB missense mutation went on a ketogenic diet for weight loss. Prior to initiating the diet, her total cholesterol was 311 mg/dL and LDL was 211 mg/dL. While on the ketogenic diet, her total cholesterol was 550 mg/dL and LDL was 454 mg/dL. Her LDL decreased to 276mg/dl on a less strict ketogenic diet. Results All three patients had a normal exercise stress test, normal carotid duplex ultrasound, and coronary calcium score of zero. They refused the initiation of a statin. All 3 patients had the Boston Heart Cholesterol Balance Test performed that directly measures the absorption markers (beta-sitosterol, campesterol and cholestanol) for circulating plasma cholesterol. Only the patient with the APOB mutation had increased intestinal absorption of cholesterol, suggesting a response to ezetimibe. She agreed to initiate ezetimibe, her LDL subsequently decreased by 52% to 132mg/dl. Conclusions We hypothesize patients with APOE variants and APOB mutations could have an exaggerated elevation of their LDL levels while on ketogenic diets. Although these 3 patients did not demonstrate progressive atherosclerosis, the long-term effect of this diet is unknown. We recommend that all patients on a ketogenic diet have their LDL monitored and if there is a significant increase, undergo genetic testing for FH, APOE and other genetic variants. Since this patient group is often reluctant to start statins, the Cholesterol Balance Test may be useful to identify patients who may respond well to ezetimibe. Nothing to disclose.

Familial Hypercholesterolemia and Elevated Lipoprotein(a): Cascade Testing and Other Implications for Contextual Models of Care.

Elevated lipoprotein(a) [Lp(a)], a predominantly genetic disorder, is a causal risk factor for atherosclerotic cardiovascular disease (ASCVD) and calcific aortic valvular disease, particularly in patients with familial hypercholesterolemia (FH), a Tier I genomic condition. The combination from birth of the cumulative exposure to elevated plasma concentrations of both Lp(a) and low-density lipoprotein is particularly detrimental and explains the enhanced morbidity and mortality risk observed in patients with both conditions. An excellent opportunity to identify at-risk patients with hyper-Lp(a) at increased risk of ASCVD is to test for hyper-Lp(a) during cascade testing for FH. With probands having FH and hyper-Lp(a), the yield of detection of hyper-Lp(a) is 1 individual for every 2.1–2.4 relatives tested, whereas the yield of detection of both conditions is 1 individual for every 3–3.4 relatives tested. In this article, we discuss the incorporation of assessment of Lp(a) in the cascade testing in FH as a feasible and crucial part of models of care for FH. We also propose a simple management tool to help physicians identify and manage elevated Lp(a) in FH, with implications for the care of Lp(a) beyond FH, noting that the clinical use of RNA therapeutics for specifically targeting the overproduction of Lp(a) in at risk patients is still under investigation.

Abstract 017: Clinical Utility Of Genetic Testing For Familial Hypercholesterolemia In A Pediatric Dyslipidemia Clinic

Background: Familial hypercholesterolemia (FH) in children is diagnosed by identification of a known FH pathogenic variant or clinical criteria. We sought to determine the number of pediatric probands undergoing genetic testing for FH that met clinical criteria, and to evaluate differences between genotype positive and negative probands. Methods: All children ≤18 years old undergoing genetic testing for suspected FH were included. Clinical FH was defined as LDL ≥160 mg/dL and family history of premature CAD in 1 st /2 nd degree relatives. Screening of 1 st /appropriate 2 nd degree family members was recommended at all visits (lipid panel or genetic test) and was complete if obtained within 1 year of proband testing. Probands were stratified based on the presence or absence of known FH pathogenic variants. Wilcoxon rank sum or chi-squared tests compared lipid panel, LP(a), BMI percentile, number of screening tests performed, and family members diagnosed with FH. Results: Of 76 probands (age 12.5±2.9 years, 57% males) with suspected FH and genetic testing; 41 (54%) were genotype positive. Genotype positive probands were more likely to meet clinical criteria (44% vs. 17%, p=0.01), but only 19/41 (46%) had a positive family history. Genotype positive probands had higher total cholesterol (mg/dL) [median (IQR): 260 (242-297) vs. 226 (215-245), p&lt;0.01] and LDL [199 mg/dL (174-229) vs. 153 mg/dL (144-171), p&lt;0.01]. Sex, BMI percentile, family history, HDL, triglycerides, and LP(a) were similar between groups. Genotype positive probands (adopted probands excluded) had more screening tests performed [median (IQR): 4 (2-6) vs. 2 (1-3), p&lt;0.01] and more new family members identified [3 (1-4) vs. 0 (0-1), p&lt;0.01]. Conclusion: Clinical criteria alone underdiagnosed FH in children and a negative family history occurred in over half of pediatric FH patients. A positive genetic diagnosis increased the number of screening tests performed and improved identification of at-risk family members. Therefore, genetic testing should be performed in all suspected pediatric FH patients.

Fast and Easy Nanopore Sequencing Workflow for Rapid Genetic Testing of Familial Hypercholesterolemia.

Familial hypercholesterolemia (FH) is an autosomal dominant lipid metabolism disorder characterized by severely elevated plasma low-density lipoprotein cholesterol levels. The disease is caused by mutations in 3 genes (LDLR, APOB and PCSK9) while over 90% of the mutations are located within the LDLR gene. Thus, genetic analysis of the LDLR gene is the first step in the genetic diagnosis of FH. However, conventional methods like Sanger and NextGen sequencing are still costly and time-consuming. In contrast, Oxford Nanopore technology sequencing is an emerging third-generation sequencing technology featured by easy operability, low cost, small size and the capability of parallel sample sequencing. Here, we present an easy Nanopore-sequencing-based workflow for the rapid genetic testing of FH taking only 3 days and costing less than $50 per sample without the requirement for deep bioinformatic knowledge. Using our workflow, we were able to identify the underlying pathogenic variants of 10 FH patients including one novel, not yet recorded pathogenic variants. Our workflow allows the rapid evaluation of the pathogenic variants by utilizing detailed variant information from Ensembl. Additionally, our workflow is not restricted to sequencing the LDLR gene alone but can be easily adapted to the other FH-causing genes and more importantly, to any desired gene contributing to any hereditary disease. Therefore, our workflow is an attractive opportunity for every diagnostic laboratory to offer fast and easy in-house genetic diagnostics.

The design and rationale of the Advancing Cardiac Care Unit-based Rapid Assessment and Treatment of hypErcholesterolemia (ACCURATE) study

Familial hypercholesterolemia (FH) is an inherited condition characterized by elevated low-density lipoprotein cholesterol (LDL-C) levels and premature atherosclerotic cardiovascular disease (ASCVD). Despite being the most common inherited cardiovascular disorder, it is still highly underdiagnosed and undertreated worldwide. We designed the Advancing Cardiac Care Unit-based Rapid Assessment and Treatment of hypErcholesterolemia (ACCURATE) study to test the hypothesis that opportunistic genetic testing for FH among patients hospitalized for acute coronary syndrome (ACS) will increase the diagnosis of FH and improve patient outcomes. ACCURATE is a non-randomized, controlled trial of patients <60 years old admitted to an acute cardiac unit with ACS and elevated LDL-C levels. The first cohort will consist of a control group of patients presenting with ACS who will be treated according to usual standard-of-care. The second cohort will consist of patients presenting with ACS in whom research-based genetic testing for FH will be performed during hospitalization and the results returned to the treating physicians. The primary endpoint will be the number of patients with a new diagnosis of FH. The secondary endpoints will be the proportion of patients who undergo intensification of lipid-lowering therapy, the lowest LDL-C level achieved, and the proportion of patients reaching guideline recommended lipid targets in the 12 months after the index ACS. To our knowledge, ACCURATE represents the first clinical trial of genetic testing for FH in the acute cardiac care setting and is expected to help identify optimal approaches to increase the diagnosis and treatment of FH.

Abstract 11337: Sensitivity Analysis of an Electronic Health Record-Based Algorithm to Facilitate Detection of Familial Hypercholesterolemia: Results in Genetically Confirmed Familial Hypercholesterolemia

Introduction: Familial hypercholesterolemia (FH) is a genetic disorder resulting in elevated LDL-C levels and increased risk of cardiovascular disease. Algorithms have been developed to facilitate FH detection. We previously developed a continuous, electronic health record (EHR)-based algorithm using the Dutch Lipid Clinical Network (DLCN) criteria, with automated correction of LDL-C levels for use of lipid-lowering-therapy (LLT). In this study, we performed a sensitivity analysis of the algorithm in patients with previously genetically confirmed FH. Methods: We selected all patients with genetically confirmed FH, seen during 2018 and 2019. DLCN scores were calculated before and after correction for LLT at the most recent visit. The primary outcome was the number of FH patients with DLCN criteria ≥6 points for LDL-C (which would have been an indication for genetic testing) before and after correction for LLT. Secondary endpoint was the additional number of patients with ≥6 points after also adding data on patient- and family history. Results: We included 222 patients with genetically confirmed FH; mean (SD) age: 50 (17) years; female: n=134 (60,4%). In total, 210 patients (94,6%) used some type of LLT. Mean (SD) LDL-C was 3,0 (1,4) mmol/L before correction for LLT and 7,5 (3,7) mmol/L after correction for LLT. Before correction for LLT, the algorithm identified 3 patients (1,4%) with ≥6 DLCN points, increasing to 59 patients (26,6%) after correction for LLT and to 76 patients (34,2%) after adding data on patient-, and family history. Conclusion: We conclude that, even after correction for LLT and addition of data on patient-, and family history, the sensitivity of a DLCN-based algorithm appeared relatively low in a population with genetically confirmed FH. Correction for LLT is important to increase sensitivity of the algorithm. Interestingly, FH detection algorithms inevitably rely on phenotypical characteristics of patients, whereas the present data show that genotypical FH does not necessarily express as phenotypical FH recognized by the DLCN-based algorithm. These data highlight the need for improvement of the DLCN-based algorithm and the importance of cascade testing for FH.