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Aim: Methylation of LDLR, PCSK9 and LDLRAP1 CpG sites was assessed in patients with familial hypercholesterolemia (FH). Methods: DNA methylation of was analyzed by pyrosequencing in 131 FH patients and 23 normolipidemic (NL) subjects.Results:  LDLR, PCSK9 and LDLRP1 methylation was similar between FH patients positive (MD) and negative (non-MD) for pathogenic variants in FH-related genes. LDLR and PCSK9 methylation was higher in MD and non-MD groups than NL subjects (p < 0.05). LDLR, PCSK9 and LDLRAP1 methylation profiles were associated with clinical manifestations and cardiovascular events in FH patients (p < 0.05).Conclusion: Differential methylation of LDLR, PCSK9 and LDLRAP1 is associated with hypercholesterolemia and cardiovascular events. This methylation profile maybe useful as a biomarker and contribute to the management of FH.

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INTRODUCTION: In Mexico, familial hypercholesterolemia (FH) is underdiagnosed, but population screening in small communities where at least one homozygous patient has already been detected results in a useful and inexpensive approach to reduce this problem. Considering that we previously reported nine homozygous cases from the state of Oaxaca, we decided to perform a population screening to identify patients with FH and to describe both their biochemical and genetic characteristics. METHODS: LDL cholesterol (LDLc) was quantified in 2,093 individuals from 11 communities in Oaxaca; either adults with LDLc levels ≥170 mg/dL or children with LDLc ≥130 mg/dL were classified as suggestive of FH and therefore included in the genetic study. LDLR and APOB (547bp fragment of exon 26) genes were screened by sequencing and MLPA analysis. RESULTS: Two hundred and five individuals had suggestive FH, with a mean LDLc of 223 ± 54 mg/dL (range: 131-383 mg/dL). Two pathogenic variants in the LDLR gene were detected in 149 individuals: c.-139_-130del (n = 1) and c.2271del (n = 148). All patients had a heterozygous genotype. With the cascade screening of their relatives (n = 177), 15 heterozygous individuals for the c.2271del variant were identified, presenting a mean LDLc of 133 ± 35 mg/dL (range: 60-168 mg/dL). CONCLUSIONS: The FH frequency in this study was 7.8% (164/2093), the highest reported worldwide. A founder effect combined with inbreeding could be responsible for the high percentage of patients with the LDLR c.2271del variant (99.4%), which allowed us to detect both significant biochemical heterogeneity and incomplete penetrance; hence, we assumed the presence of phenotype-modifying variants.

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PURPOSE OF REVIEW: Heterozygous familial hypercholesterolemia (HeFH) is the most common monogenic autosomal dominant disorder. However, the condition is often underdiagnosed and undertreated. The objective of this review is to provide an update on the risk stratification in patients with HeFH, incorporating new cardiovascular imaging techniques, various biomarkers, and genetic studies. RECENT FINDINGS: The diagnosis of HeFH places patients in a high cardiovascular risk category due to the increased incidence of premature atherosclerotic cardiovascular disease. However, the level of risk varies significantly among different individuals with HeFH. Achieving an optimal stratification of cardiovascular risk is crucial for establishing appropriate and accurate treatment and management strategies. Different new tools such as risk scores have emerged in recent years, aiding physicians in assessing the risk stratification for HeFH using imaging, biomarkers, and genetics. This review emphasizes that not all patients with HeFH face the same cardiovascular risk. By utilizing different assessment tools, we can identify those who require more intensive monitoring, follow-up, and treatment.

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Familial hypercholesterolemia (FH) is a disorder of lipid metabolism that causes elevated low-density lipoprotein cholesterol (LDL-c) and increased premature atherosclerosis risk. Statins inhibit endogenous cholesterol biosynthesis, which reduces LDL-c plasma levels and prevent from cardiovascular events. This study aimed to explore the effects of statin treatment on serum lipidomic profile and to identify biomarkers of response in subjects with FH. Seventeen adult FH patients underwent a 6-week washout followed by 4-week treatment with atorvastatin (80 mg/day) or rosuvastatin (40 mg/day). LDL-c response was considered good (40-70 % reduction, n = 9) or poor (3-33 % reduction, n = 8). Serum lipidomic profile was analyzed by ultra-high-performance liquid chromatography combined with electrospray ionization tandem time-of-flight mass spectrometry, and data were analyzed using MetaboAnalyst v5.0. Lipidomic analysis identified 353 lipids grouped into 16 classes. Statin treatment reduced drastically 8 of 13 lipid classes, generating a characteristic lipidomic profile with a significant contribution of phosphatidylinositols (PI) 16:0/18:2, 18:0/18:1 and 18:0/18:2; and triacylglycerols (TAG) 18:2x2/18:3, 18:1/18:2/18:3, 16:1/18:2x2, 16:1/18:2/18:3 and 16:1/18:2/Arachidonic acid (p-adjusted <0.05). Biomarker analysis implemented in MetaboAnalyst subsequently identified PI 16:1/18:0, 16:0/18:2 and 18:0/18:2 as predictors of statin response with and receiver operating characteristic (ROC) areas under the curve of 0.98, 0.94 and 0.91, respectively. In conclusion, statins extensively modulate the overall serum lipid composition of FH individuals and these findings suggest that phosphatidyl-inositol molecules are potential predictive biomarkers of statin response.

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Familial hypercholesterolemia (FH) is caused by mutations in the gene that encodes the low-density lipoprotein (LDL) receptor, which leads to an excessive increase in plasma LDL cholesterol levels. Previous studies have shown that FH is associated with gliosis, blood-brain barrier dysfunction, and memory impairment, but the mechanisms associated with these events are still not fully understood. Therefore, we aimed to investigate the role of microgliosis in the neurochemical and behavioral changes associated with FH using LDL receptor knockout (LDLr-/- ) mice. We noticed that microgliosis was more severe in the hippocampus of middle-aged LDLr-/- mice, which was accompanied by microglial morphological changes and alterations in the immunocontent of synaptic protein markers. At three months of age, the LDLr-/- mice already showed increased microgliosis and decreased immunocontent of claudin-5 in the prefrontal cortex (PFC). Subsequently, 6-month-old male C57BL/6 wild-type and LDLr-/- mice were treated once daily for 30 days with minocycline (a pharmacological inhibitor of microglial cell reactivity) or vehicle (saline). Adult LDLr-/- mice displayed significant hippocampal memory impairment, which was ameliorated by minocycline treatment. Non-treated LDLr-/- mice showed increased microglial density in all hippocampal regions analyzed, a process that was not altered by minocycline treatment. Region-specific microglial morphological analysis revealed different effects of genotype or minocycline treatment on microglial morphology, depending on the hippocampal subregion analyzed. Moreover, 6-month-old LDLr-/- mice exhibited a slight but not significant increase in IBA-1 immunoreactivity in the PFC, which was reduced by minocycline treatment without altering microglial morphology. Minocycline treatment also reduced the presence of microglia within the perivascular area in both the PFC and hippocampus of LDLr-/- mice. However, no significant effects of either genotype or minocycline treatment were observed regarding the phagocytic activity of microglia in the PFC and hippocampus. Our results demonstrate that hippocampal microgliosis, microglial morphological changes, and the presence of these glial cells in the perivascular area, but not increased microglial phagocytic activity, are associated with cognitive deficits in a mouse model of FH.

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BACKGROUND: Familial hypercholesterolemia (FH) is caused by pathogenic variants in low-density lipoprotein (LDL) receptor (LDLR) or its associated genes, including apolipoprotein B (APOB), proprotein convertase subtilisin/kexin type 9 (PCSK9), and LDLR adaptor protein 1 (LDLRAP1). However, approximately 40% of the FH patients clinically diagnosed (based on FH phenotypes) may not carry a causal variant in a FH-related gene. Variants located at 3' untranslated region (UTR) of FH-related genes could elucidate mechanisms involved in FH pathogenesis. This study used a computational approach to assess the effects of 3'UTR variants in FH-related genes on miRNAs molecular interactions and to explore the association of these variants with molecular diagnosis of FH. METHODS AND RESULTS: Exons and regulatory regions of FH-related genes were sequenced in 83 FH patients using an exon-target gene sequencing strategy. In silico prediction tools were used to study the effects of 3´UTR variants on interactions between miRNAs and target mRNAs. Pathogenic variants in FH-related genes (molecular diagnosis) were detected in 44.6% FH patients. Among 59 3'UTR variants identified, LDLR rs5742911 and PCSK9 rs17111557 were associated with molecular diagnosis of FH, whereas LDLR rs7258146 and rs7254521 and LDLRAP1 rs397860393 had an opposite effect (p < 0.05). 3´UTR variants in LDLR (rs5742911, rs7258146, rs7254521) and PCSK9 (rs17111557) disrupt interactions with several miRNAs, and more stable bindings were found with LDLR (miR-4435, miR-509-3 and miR-502) and PCSK9 (miR-4796). CONCLUSION: LDLR and PCSK9 3´UTR variants disturb miRNA:mRNA interactions that could affect gene expression and are potentially associated with molecular diagnosis of FH.

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Familial hypercholesterolemia (FH) is a monogenic disease characterized by high plasma low-density lipoprotein cholesterol (LDL-c) levels and increased risk of premature atherosclerotic cardiovascular disease. Mutations in FH-related genes account for 40% of FH cases worldwide. In this study, we aimed to assess the pathogenic variants in FH-related genes in the Brazilian FH cohort FHBGEP using exon-targeted gene sequencing (ETGS) strategy. FH patients (n = 210) were enrolled at five clinical sites and peripheral blood samples were obtained for laboratory testing and genomic DNA extraction. ETGS was performed using MiSeq platform (Illumina). To identify deleterious variants in LDLR, APOB, PCSK9, and LDLRAP1, the long-reads were subjected to Burrows-Wheeler Aligner (BWA) for alignment and mapping, followed by variant calling using Genome Analysis Toolkit (GATK) and ANNOVAR for variant annotation. The variants were further filtered using in-house custom scripts and classified according to the American College Medical Genetics and Genomics (ACMG) guidelines. A total of 174 variants were identified including 85 missense, 3 stop-gain, 9 splice-site, 6 InDel, and 71 in regulatory regions (3'UTR and 5'UTR). Fifty-two patients (24.7%) had 30 known pathogenic or likely pathogenic variants in FH-related genes according to the American College Medical and Genetics and Genomics guidelines. Fifty-three known variants were classified as benign, or likely benign and 87 known variants have shown uncertain significance. Four novel variants were discovered and classified as such due to their absence in existing databases. In conclusion, ETGS and in silico prediction studies are useful tools for screening deleterious variants and identification of novel variants in FH-related genes, they also contribute to the molecular diagnosis in the FHBGEP cohort.

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BACKGROUND AND AIMS: Familial hypercholesterolemia (FH) variants are associated with higher atherosclerotic cardiovascular disease risk (ASCVD) even when compared with other forms of severe hypercholesterolemia, especially in young people. Lipid lowering therapies (LLT) may change hypercholesterolemia natural history. This study aimed at evaluating factors associated with occurrence of ASCVD in old severe hypercholesterolemics diagnosed or not with FH and undergoing LLT. METHODS: Hypercholesterolemic individuals ≥60 years participating on a genetic cascade screening for FH were divided in 4 groups (2 × 2) according to the presence (variant+) or not (variant-) of FH genetic variants and previous ASCVD (ASCVD+ and ASCVD-). Biomarkers associated with new incident ASCVD events were tested using Cox models. Continuous data shown as medians (%25; %75). RESULTS: From 4,111 genotyped individuals, 377 (9.1%) were elderly [age 66 (63; 71) years], 28.9% males, 42.7% variant+, 32.1% with previous ASCVD, LLT duration 9 (5; 16) years, and on treatment LDL-cholesterol 144 (109; 200) mg/dL. After 4.8 (7; 3) years of follow up there were 47 incident events (12.4%, 2.7% patient/year). The annualized event rates were 0.8% (95% CI 0.36%; 1.70%), 2.3% (95% CI 1.3%; 4.1%), 5.2% (95% CI 2.8%; 9.7%) and 6.3% (95% CI 4.0%; 10.0%) respectively for groups variant-/ASCVD-, variant+/ASCVD-, variant-/ASCVD+ and, variant+/ASCVD+ (p log rank p < 0.001). Only presence of previous ASCVD was independently associated with incident ASCVD [hazard ratio 3.236 (95%CI 1.497-6.993, p = 0.003)]. No interaction was found for previous ASCVD and variants. CONCLUSIONS: In old severe hypercholesterolemic individuals undergoing long-term LLT previous ASCVD was associated with incident events while FH causing variants were not.

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Familial hypercholesterolemia (FH) is caused by deleterious mutations in the LDLR that increase markedly low-density lipoprotein (LDL) cholesterol and cause premature atherosclerotic cardiovascular disease. Functional effects of pathogenic LDLR variants identified in Brazilian FH patients were assessed using in vitro and in silico studies. Variants in LDLR and other FH-related genes were detected by exon-target gene sequencing. T-lymphocytes were isolated from 26 FH patients, and 3 healthy controls and LDLR expression and activity were assessed by flow cytometry and confocal microscopy. The impact of LDLR missense variants on protein structure was assessed by molecular modeling analysis. Ten pathogenic or likely pathogenic LDLR variants (six missense, two stop-gain, one frameshift, and one in splicing region) and six non-pathogenic variants were identified. Carriers of pathogenic and non-pathogenic variants had lower LDL binding and uptake in activated T-lymphocytes compared to controls (p < 0.05), but these variants did not influence LDLR expression on cell surface. Reduced LDL binding and uptake was also observed in carriers of LDLR null and defective variants. Modeling analysis showed that p.(Ala431Thr), p.(Gly549Asp) and p.(Gly592Glu) disturb intramolecular interactions of LDLR, and p.(Gly373Asp) and p.(Ile488Thr) reduce the stability of the LDLR protein. Docking and molecular interactions analyses showed that p.(Cys184Tyr) and p.(Gly373Asp) alter interaction of LDLR with Apolipoprotein B (ApoB). In conclusion, LDLR null and defective variants reduce LDL binding capacity and uptake in activated T-lymphocytes of FH patients and LDLR missense variants affect LDLR conformational stability and dissociation of the LDLR-ApoB complex, having a potential role in FH pathogenesis.

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OBJECTIVE: Our study aimed to evaluate the expected cost-effectiveness of pediatric universal screening for the early diagnosis of familial hypercholesterolemia in Argentina using a probabilistic model. METHODS: Two different healthcare technologies were compared: (1) Universal screening of hypercholesterolemia at 6 years of age and (2) previous diagnostic situation (comparator). The perspective of the public Argentine healthcare system funded by the National Ministry of Health was used, considering only direct costs. Effectiveness was evaluated in terms of the number of life-years gained (LYG) and quality-adjusted life-years (QALYs) obtained by identifying familial hypercholesterolemia through each of the screening strategies. Only direct costs of screening and treatment of each strategy were evaluated. The time horizon was extended to 60 years. Future avoided costs of prevented coronary events were also included. Cost-effectiveness was measured in terms of the incremental cost-effectiveness ratio (ICER) per LYG and QALYs. Different scenarios were evaluated: (1) only index case, (2) index case and first-degree relatives, and (3) index case and first-degree relatives measuring QALYs. Sensitivity studies were conducted. RESULTS: Each identified child complying with follow-up visits and treatment gains 8.14 life-years. The ICER values obtained were 1465.35 USD/LYG and 1726.50 USD/LYG when applying a discount rate of 5%. The ICER was 10%-17% of the gross domestic product per capita in Argentina (mean 2010-2019: 12 446 USD) and did not exceed the minimum annual retirement income. CONCLUSION: Pediatric universal screening for familial hypercholesterolemia could be considered a cost-effective health technology in Argentina.

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PCSK9 gain-of-function (GOF) variants increase degradation of low-density lipoprotein receptor (LDLR) and are potentially associated with Familial Hypercholesterolemia (FH). This study aimed to explore the effects of PCSK9 missense variants on protein structure and interactions with LDLR using molecular modeling analyses and in vitro functional studies. Variants in FH-related genes were identified in a Brazilian FH cohort using an exon-target gene sequencing strategy. Eight PCSK9 missense variants in pro- [p.(E32K) and p.(E57K)], catalytic [p.(R237W), p.(P279T) and p.(A443T)], and C-terminal histidine-cysteine rich (CHR) [p.(R469W), p.(Q619P) and p.(R680Q)] domains were identified. Molecular dynamics analyses revealed that GOF variants p.(E32K) and p.(R469W) increased extreme motions in PCSK9 amino acid backbone fluctuations and affected Hbond and water bridge interactions between the pro-domain and CM1 region of the CHR domain. HEK293FT cells transfected with plasmids carrying p.(E32K) and p.(R469W) variants reduced LDLR expression (8.7 % and 14.8 %, respectively) compared to wild type (p < 0.05) but these GOF variants did not affect PCSK9 expression and secretion. The missense variants p.(P279T) and p.(Q619P) also reduced protein stability and altered Hbond interactions. In conclusion, PCSK9 p.(E32K), p.(R469W), p.(P279T) and p.(Q619P) variants disrupt intramolecular interactions that are essential for PCSK9 structural conformation and biological activity and may have a potential role in FH pathogenesis.

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OBJECTIVE: To identify childhood and parental factors associated with initiation of statin therapy in children with heterozygous familial hypercholesterolemia (HeFH), including underlying genetic diagnosis or parental premature atherosclerotic cardiovascular disease (ASCVD). STUDY DESIGN: This multicenter cohort study included 245 HeFH child-parent pairs from the REFERCHOL national register (2014-2020). Demographic and clinical characteristics at the last visit were collected. Vascular disease in parents was defined as a history of ASCVD, and/or a coronary artery calcium score >100, and/or stenosis of >50% in at least carotid artery. Statistical analyses included descriptive analysis, logistic regression for univariate and multivariate effects of statins, and a sensitivity analysis combining the characteristics of children and parents. RESULTS: Among the 245 children in the study cohort, 135 (58%), with a mean age of 14 ± 3 years, were treated with a statin. In multivariable analysis, the predictive childhood factors associated with statin treatment were genetic diagnosis (OR, 2.5; 95% CI, 1.3 to 4.9; P = .01), older age (OR, 4.4; 95% CI, 1.8-10.6; P = .01), more than 2 visits (OR, 2.36; 95% CI, 1.18-4.73; P = .015), and longer duration of follow-up (OR, 1.3; 95% CI, 1.1-1.6; P < .001). The predictive parental factor associated with childhood treatment was the presence of vascular disease (OR, 2.4; 95% CI, 1.0-5.7; P = .04). CONCLUSIONS: HeFH confirmed by DNA testing during childhood and a history of vascular disease in parents were independently associated with statin treatment in children with HeFH. Genetic diagnosis may be useful for cardiovascular prevention in children.

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Introducción: La hipercolesterolemia familiar es una enfermedad con alta prevalencia, no tratada acorta la esperanza de vida, por lo que el diagnóstico a edades tempranas resulta fundamental. Las pruebas genéticas constituyen el gold standard para el diagnóstico de hipercolesterolemia familiar, sin embargo, la no disponibilidad del test genético no debe constituir un impedimento para la adecuada conducta en estos casos. Objetivo: Identificar criterios clínicos predictores en el diagnóstico por pesquisa de la hipercolesterolemia familiar. Métodos: Se realizó un estudio descriptivo prospectivo a partir de una muestra de 393 pacientes (casos índices) de HF en el Hospital Clínico Quirúrgico Hermanos Ameijeiras; durante el período 2008-2018. Resultados: En la pesquisa familiar fueron identificados 177 (15,66 por ciento) nuevos casos de hipercolesterolemia familiar, de ellos se clasifican como casos positivos 35 (19,77 por ciento), casos probables 58 (32,77 por ciento) y casos posibles 84 (47,46 por ciento). Las categorías del estrato Make early diagnosis to prevent early death MEDPED y la edad del caso índice resultaron ser las variables clínicas de interés con mayor probabilidad para identificar nuevos casos de hipercolesterolemia familiar. Conclusiones: los criterios clínicos estandarizados de la escala make early diagnosis to prevent early death P y la edad del caso índice resultaron ser indicadores predictivos de gran valor para identificar y estratificar casos con variantes fenotípicas de hipercolesterolemia familiar(AU)

Introduction: Familial hypercholesterolemia is a disease with high prevalence; it shortens life expectancy if it is not treated, so early diagnosis is essential. Genetic tests are the gold standard for the diagnosis of familial hypercholesterolemia, however, the unavailability of the genetic test should not be an obstacle to proper conduct in these cases. Objective: To identify predictive clinical criteria in the diagnosis by screening of familial hypercholesterolemia. Methods: A prospective descriptive study was carried out from a sample of 393 patients (index cases) of FH at Hermanos Ameijeiras Surgical Clinical Hospital from 2008 to 2018. Results: In the family investigation, 177 (15.66 percent) new cases of familial hypercholesterolemia were identified, 35 of them (19.77 percent) are classified as positive cases, 58 (32.77 percent) as probable cases and 84 as possible cases (47.46 percent)The stratum categories of Make Early Diagnosis to Prevent Early Death (MEDPED) and the age of the index case turned out to be the clinical variables of interest with the greatest probability to identify new cases of familial hypercholesterolemia. Conclusions: The standardized clinical criteria of the make early diagnosis to prevent early death P scale and the age of the index case turned out to be highly valuable predictive indicators to identify and stratify cases with phenotypic variants of familial hypercholesterolemia(AU)

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Statins are the first-line treatment for familial hypercholesterolemia (FH), but response is highly variable due to genetic and nongenetic factors. Here, we explored the association between response and genetic variability in 114 Brazilian adult FH patients. Specifically, a panel of 84 genes was analyzed by exon-targeted gene sequencing (ETGS), and the functional impact of variants in pharmacokinetic (PK) genes was assessed using an array of functionality prediction methods. Low-density lipoprotein cholesterol (LDL-c) response to statins (reduction ≥ 50%) and statin-related adverse event (SRAE) risk were assessed in carriers of deleterious variants in PK-related genes using multivariate linear regression analyses. Fifty-eight (50.8%) FH patients responded to statins, and 24 (21.0%) had SRAE. Results of the multivariate regression analysis revealed that ABCC1 rs45511401 significantly increased LDL-c reduction after statin treatment (p < 0.05). In silico analysis of the amino-acid change using molecular docking showed that ABCC1 rs45511401 possibly impairs statin efflux. Deleterious variants in PK genes were not associated with an increased risk of SRAE. In conclusion, the deleterious variant ABCC1 rs45511401 enhanced LDL-c response in Brazilian FH patients. As such, this variant might be a promising candidate for the individualization of statin therapy.

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PURPOSE OF REVIEW: Familial hypercholesterolemia is a high cardiovascular risk disorder. We will review the role of lipoprotein(a) in cardiovascular risk and in aortic valve stenosis in familial hypercholesterolemia, as well as its association with their phenotype, and strategies to identify this high-risk population. RECENT FINDINGS: Patients with familial hypercholesterolemia have higher lipoprotein(a) levels mainly due to an increased frequency of LPA variants, and the cardiovascular risk is increased twofolds when both conditions coexist. Also, an increased risk for aortic valve stenosis and valve replacement has been observed with high lipoprotein(a) levels. Assessment of lipoprotein(a) during the cascade screening for familial hypercholesterolemia is a good opportunity to identify this high-risk population. High cardiovascular risk in familial hypercholesterolemia is increased even more when lipoprotein(a) is also elevated. Measurement of lipoprotein(a) in these patients is crucial to identify those subjects who need to intensify LDL-cholesterol reduction pending availability of lipoprotein(a)-specific treatments.

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Resumo Fundamento A hipercolesterolemia familiar (HF) é uma doença genética dominante que se caracteriza por níveis sanguíneos elevados de colesterol de lipoproteína de baixa densidade (LDL-C), e está associada à ocorrência de doença cardiovascular precoce. No Brasil, o HipercolBrasil, que é atualmente o maior programa de rastreamento em cascata para HF, já identificou mais de 2.000 indivíduos com variantes genéticas causadoras de HF. A abordagem padrão baseia-se no rastreamento em cascata de casos índices referidos, indivíduos com hipercolesterolemia e suspeita clínica de HF. Objetivos Realizar rastreamento direcionado de 11 pequenos municípios brasileiros com suspeita de alta prevalência de indivíduos com HF. Métodos A seleção dos municípios ocorreu de 3 maneiras: 1) municípios em que houve suspeita de efeito fundador (4 municípios); 2) municípios em uma região com altas taxas de infarto do miocárdio precoce, conforme descrito pelo banco de dados do Sistema Único de Saúde (2 municípios); e 3) municípios geograficamente próximos a outros municípios com alta prevalência de indivíduos com HF (5 municípios). A significância estatística foi considerada como valor p < 0,05. Resultados Foram incluídos 105 casos índices e 409 familiares de primeiro grau. O rendimento dessa abordagem foi de 4,67 familiares por caso índice, o qual é significativamente melhor (p < 0,0001) do que a taxa geral do HipercolBrasil (1,59). Identificamos 36 CIs com variante patogênica ou provavelmente patogênica para HF e 240 familiares de primeiro grau afetados. Conclusão: Nossos dados sugerem que, uma vez detectadas, regiões geográficas específicas justificam uma abordagem direcionada para a identificação de aglomerações de indivíduos com HF.

Abstract Background Familial hypercholesterolemia (FH) is a genetic disease characterized by elevated serum levels of low-density lipoprotein cholesterol (LDL-C), and it is associated with the occurrence of early cardiovascular disease. In Brazil, HipercolBrasil, which is currently the largest FH cascade screening program, has already identified more than 2000 individuals with causal genetic variants for FH. The standard approach is based on cascade screening of referred index cases, individuals with hypercholesterolemia and clinical suspicion of FH. Objectives To perform targeted screening of 11 small Brazilian cities with a suspected high prevalence of people with FH. Methods The selection of cities occurred in 3 ways: 1) cities in which a founder effect was suspected (4 cities); 2) cities in a region with high rates of early myocardial infarction as described by the National Health System database (2 cities); and 3) cities that are geographically close to other cities with a high prevalence of individuals with FH (5 cities). Statistical significance was considered as p value < 0.05. Results One hundred and five index cases and 409 first-degree relatives were enrolled. The yield of such approach of 4.67 relatives per index case was significantly better (p < 0.0001) than the general HipercolBrasil rate (1.59). We identified 36 IC with a pathogenic or likely pathogenic variant for FH and 240 affected first-degree relatives. Conclusion Our data suggest that, once detected, specific geographical regions warrant a target approach for identification of clusters of individuals with FH.