Browsing by Author "Chora, Joana R."
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- Adaptation of ACMG/AMP guidelines for standardized variant interpretation in familial hypercholesterolemiaPublication . Iacocca, Michael A.; Chora, Joana R.; Freiberger, Tomas; Carrie, Alain; Leigh, Sarah E.; Kurtz, C. Lisa; Tichy, Lukas; DiStefano, Marina T.; Wand, Hannah; Defesche, Joep; Sijbrands, Eric J.; Hegele, Robert A; Knowles, Joshua W.; Bourbon, Mafalda; On behalf of the ClinGen FH Variant Curation Expert PanelBackground: The successes of clinical genetics rely on accurate DNA variant interpretation for the purpose of informing diagnosis and treatment; However, this practice is often rudimentary and differs among diagnostic laboratories, leading to inconsistencies in pathogenicity classification: In response, the Clinical Genome (ClinGen) Resource consortium approves expert panels to recommend disease-specific guidelines to achieve evidence-based, standardized variant curation practice.
- ClinVar database of global familial hypercholesterolemia-associated DNA variantsPublication . Iacocca, Michael A.; Chora, Joana R.; Carrié, Alain; Freiberger, Tomáš; Leigh, Sarah E.; Defesche, Joep C.; Kurtz, C. Lisa; DiStefano, Marina T.; Santos, Raul D.; Humphries, Steve E.; Mata, Pedro; Jannes, Cinthia E.; Hooper, Amanda J.; Wilemon, Katherine A.; Benlian, Pascale; O'Connor, Robert; Garcia, John; Wand, Hannah; Tichy, Lukáš; Sijbrands, Eric J.; Hegele, Robert A.; Bourbon, Mafalda; Knowles, Joshua W.; on behalf of the ClinGen FH Variant Curation Expert PanelAccurate and consistent variant classification is imperative for incorporation of rapidly developing sequencing technologies into genomic medicine for improved patient care. An essential requirement for achieving standardized and reliable variant interpretation is data sharing, facilitated by a centralized open-source database. Familial hypercholesterolemia (FH) is an exemplar of the utility of such a resource: it has a high incidence, a favorable prognosis with early intervention and treatment, and cascade screening can be offered to families if a causative variant is identified. ClinVar, an NCBI-funded resource, has become the primary repository for clinically relevant variants in Mendelian disease, including FH. Here, we present the concerted efforts made by the Clinical Genome Resource, through the FH Variant Curation Expert Panel and global FH community, to increase submission of FH-associated variants into ClinVar. Variant-level data was categorized by submitter, variant characteristics, classification method, and available supporting data. To further reform interpretation of FH-associated variants, areas for improvement in variant submissions were identified; these include a need for more detailed submissions and submission of supporting variant-level data, both retrospectively and prospectively. Collaborating to provide thorough, reliable evidence-based variant interpretation will ultimately improve the care of FH patients.
- Contemporary Homozygous Familial Hypercholesterolemia in the United States: Insights From the CASCADE FH RegistryPublication . Cuchel, Marina; Lee, Paul C.; Hudgins, Lisa C.; Duell, P. Barton; Ahmad, Zahid; Baum, Seth J.; Linton, MacRae F.; de Ferranti, Sarah D.; Ballantyne, Christie M.; Larry, John A.; Hemphill, Linda C.; Kindt, Iris; Gidding, Samuel S.; Martin, Seth S.; Moriarty, Patrick M.; Thompson, Paul P.; Underberg, James A.; Guyton, John R.; Andersen, Rolf L.; Whellan, David J.; Benuck, Irwin; Kane, John P.; Myers, Kelly; Howard, William; Staszak, David; Jamison, Allison; Card, Mary C.; Bourbon, Mafalda; Chora, Joana R.; Rader, Daniel J.; Knowles, Joshua W.; Wilemon, Katherine; McGowan, Mary P.Background: Homozygous familial hypercholesterolemia (HoFH) is a rare, treatment-resistant disorder characterized by earlyonset atherosclerotic and aortic valvular cardiovascular disease if left untreated. Contemporary information on HoFH in the United States is lacking, and the extent of underdiagnosis and undertreatment is uncertain. Methods and Results: Data were analyzed from 67 children and adults with clinically diagnosed HoFH from the CASCADE (Cascade Screening for Awareness and Detection) FH Registry. Genetic diagnosis was confirmed in 43 patients. We used the clinical characteristics of genetically confirmed patients with HoFH to query the Family Heart Database, a US anonymized payer health database, to estimate the number of patients with similar lipid profiles in a “real-world” setting. Untreated lowdensity lipoprotein cholesterol levels were lower in adults than children (533 versus 776mg/dL; P=0.001). At enrollment, atherosclerotic cardiovascular disease and supravalvular and aortic valve stenosis were present in 78.4% and 43.8% and 25.5% and 18.8% of adults and children, respectively. At most recent follow-up, despite multiple lipid-lowering treatment, low-density lipoprotein cholesterol goals were achieved in only a minority of adults and children. Query of the Family Heart Database identified 277 individuals with profiles similar to patients with genetically confirmed HoFH. Advanced lipid-lowering treatments were prescribed for 18%; 40% were on no lipid-lowering treatment; atherosclerotic cardiovascular disease was reported in 20%; familial hypercholesterolemia diagnosis was uncommon. Conclusions: Only patients with the most severe HoFH phenotypes are diagnosed early. HoFH remains challenging to treat. Results from the Family Heart Database indicate HoFH is systemically underdiagnosed and undertreated. Earlier screening, aggressive lipid-lowering treatments, and guideline implementation are required to reduce disease burden in HoFH.
- Estudo Português de Hipercolesterolemia Familiar: 1999-2020Publication . Medeiros, Ana M.; Alves, Ana C.; Chora, Joana R.; Bourbon, MafaldaA Hipercolesterolemia Familiar (FH) é uma doença genética do metabolismo dos lípidos, para a qual existem métodos de diagnóstico e tratamentos eficazes disponíveis. Em Portugal estima-se que existam entre 20 000–33 000 pessoas com FH (prevalência 1:500–1:300). Indivíduos com FH possuem um elevado risco de desenvolver uma doença cardiovascular prematura (DCV), pois apresentam valores de colesterol elevados desde a nascença. O diagnóstico genético inclui o estudo de 3 genes associados à FH: LDLR, APOB, PCSK93. O Estudo Português de Hipercolesterolemia Familiar teve início em 1999 e tem como objetivo identificar a causa da genética da hipercolerolemia em indivíduos com critérios clínicos de FH.
- Familial hypercholesterolemiaassociated variants in ClinVarPublication . Chora, Joana R.; Iacocca, Michael A.; Carrié, Alain; Freiberger, Tomáš; Leigh, Sarah E.; Defesche, Joep C.; Kurtz, C. Lisa; DiStefano, Marina T.; Santos, Raul D.; Humphries, Steve E.; Mata, Pedro; Jannes, Cinthia E.; Hooper, Amanda J.; Wilemon, Katherine A.; Benlian, Pascale; O'Connor, Robert; Garcia, John; Wand, Hannah; Tichý, Lukáš; Sijbrands, Eric J.; Hegele, Robert A.; Bourbon, Mafalda; Knowles, Joshua W.; On behalf of the ClinGen FH Variant Curation Expert PanelFamilial Hypercholesterolemia (FH): Lipid metabolism autosomal dominant condition; Patients present elevated low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) values since birth - elevated cardiovascular risk if untreated; High heterozygote prevalence (1/250-500); Homozygous rare (1/300 000-1 000 000); Caused by pathogenic variants in LDLR (>90%), APOB (5-10%) and PCSK9 (1-3%) genes.
- Genomics of familial hypercholesterolaemiaPublication . Alves, Ana C.; Chora, Joana R.; Bourbon, MafaldaFamilial hypercholesterolaemia is an autosomal dominant disorder of lipid metabolism characterized by elevated levels of LDL-C and increased cardiovascular risk. Although the disorder can be diagnosed based on established clinical criteria, only the genetic diagnosis confirms the clinical suspicion. There are three main genes associated with familial hypercholesterolaemia: LDL receptor (LDLR), responsible for more than 90% of the cases, apolipoprotein B (APOB), responsible for 5–10% of the cases and Proprotein Convertase Subtilisin/ Kexin Type 9 (PCSK9), responsible for up to 3% of the cases. However, reporting of situations where there is an overlap of the familial hypercholesterolaemia phenotype and other conditions is now growing. (...)
- Improving the Detection of Potential Cases of Familial Hypercholesterolemia: Could Machine Learning Be Part of the Solution?Publication . Stevens, Christophe A.T.; Vallejo‐Vaz, Antonio J.; Chora, Joana R.; Barkas, Fotis; Brandts, Julia; Mahani, Alireza; Abar, Leila; Sharabiani, Mansour T.A.; Ray, Kausik K.Background: Familial hypercholesterolemia (FH), while highly prevalent, is a significantly underdiagnosed monogenic disorder. Improved detection could reduce the large number of cardiovascular events attributable to poor case finding. We aimed to assess whether machine learning algorithms outperform clinical diagnostic criteria (signs, history, and biomarkers) and the recommended screening criteria in the United Kingdom in identifying individuals with FH-causing variants, presenting a scalable screening criteria for general populations. Methods and results: Analysis included UK Biobank participants with whole exome sequencing, classifying them as having FH when (likely) pathogenic variants were detected in their LDLR, APOB, or PCSK9 genes. Data were stratified into 3 data sets for (1) feature importance analysis; (2) deriving state-of-the-art statistical and machine learning models; (3) evaluating models' predictive performance against clinical diagnostic and screening criteria: Dutch Lipid Clinic Network, Simon Broome, Make Early Diagnosis to Prevent Early Death, and Familial Case Ascertainment Tool. One thousand and three of 454 710 participants were classified as having FH. A Stacking Ensemble model yielded the best predictive performance (sensitivity, 74.93%; precision, 0.61%; accuracy, 72.80%, area under the receiver operating characteristic curve, 79.12%) and outperformed clinical diagnostic criteria and the recommended screening criteria in identifying FH variant carriers within the validation data set (figures for Familial Case Ascertainment Tool, the best baseline model, were 69.55%, 0.44%, 65.43%, and 71.12%, respectively). Our model decreased the number needed to screen compared with the Familial Case Ascertainment Tool (164 versus 227). Conclusions: Our machine learning-derived model provides a higher pretest probability of identifying individuals with a molecular diagnosis of FH compared with current approaches. This provides a promising, cost-effective scalable tool for implementation into electronic health records to prioritize potential FH cases for genetic confirmation.
- Specification of ACMG AMP Guidelines for Variant Interpretation in Familial HypercholesterolemiaPublication . Chora, Joana R.; Lacocca, Michael A.; Carrié, Alain; Leigh, Sarah E.; Tichý, Lukáš; Kurtz, C. Lisa; Freiberger, Tomas; Sijbrands, Eric J.; Hegele, Robert A.; Knowles, Joshua W.; Bourbon, MafaldaBackground and Aims: the general ACMG/AMP guidelines for standardized variant interpretation in Mendelian disorders are a great asset in determining variants’ pathogenicity, but need to be adapted to each specific gene and disease.
- Specification of ACMG/AMP variant classification guidelines for Familial Hypercholesterolemia – a ClinGen FH Variant Curation Committee Pilot StudyPublication . Kurtz, C. Lisa; Carrie, Alain; Chora, Joana R.; Iacocca, Michael; Leigh, Sarah; Freiberger, Tomas; Tichy, Lukas; Defesche, Joep; Hegele, Robert; Sijbrands, Eric; Knowles, Josh; Bourbon, MafaldaFamilial hypercholesterolemia (FH) is a common autosomal dominant disorder (~1:250 individuals affected) of lipid metabolism, associated with an increased risk of cardiovascular disease. Individuals with FH characteristically present with severely elevated blood cholesterol levels, which leads to atherosclerotic plaque formation and subsequently, myocardial infarction due to premature coronary artery disease. Three main causative genes have been associated with FH: LDLR, APOB and PCSK9. Diagnosis is critical for early intervention and treatment, and it is imperative that family members of affected individuals be identified as early as possible.
- The Clinical Genome Resource (ClinGen) Familial Hypercholesterolemia Variant Curation Expert Panel consensus guidelines for LDLR variant classificationPublication . Chora, Joana R.; Iacocca, Michael A.; Tichý, Lukáš; Wand, Hannah; Kurtz, C. Lisa; Zimmermann, Heather; Leon, Annette; Williams, Maggie; Humphries, Steve E.; Hooper, Amanda J.; Trinder, Mark; Brunham, Liam R.; Costa Pereira, Alexandre; Jannes, Cinthia E.; Chen, Margaret; Chonis, Jessica; Wang, Jian; Kim, Serra; Johnston, Tami; Soucek, Premysl; Kramarek, Michal; Leigh, Sarah E.; Carrié, Alain; Sijbrands, Eric J.; Hegele, Robert A.; Freiberger, Tomáš; Knowles, Joshua W.; Bourbon, Mafalda; ClinGen Familial Hypercholesterolemia Expert PanelPurpose: In 2015, the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) published consensus standardized guidelines for sequence-level variant classification in Mendelian disorders. To increase accuracy and consistency, the Clinical Genome Resource Familial Hypercholesterolemia (FH) Variant Curation Expert Panel was tasked with optimizing the existing ACMG/AMP framework for disease-specific classification in FH. In this study, we provide consensus recommendations for the most common FH-associated gene, LDLR, where >2300 unique FH-associated variants have been identified. Methods: The multidisciplinary FH Variant Curation Expert Panel met in person and through frequent emails and conference calls to develop LDLR-specific modifications of ACMG/AMP guidelines. Through iteration, pilot testing, debate, and commentary, consensus among experts was reached. Results: The consensus LDLR variant modifications to existing ACMG/AMP guidelines include (1) alteration of population frequency thresholds, (2) delineation of loss-of-function variant types, (3) functional study criteria specifications, (4) cosegregation criteria specifications, and (5) specific use and thresholds for in silico prediction tools, among others. Conclusion: Establishment of these guidelines as the new standard in the clinical laboratory setting will result in a more evidence-based, harmonized method for LDLR variant classification worldwide, thereby improving the care of patients with FH.