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Bou Ghannam A, Istambouli R, Hamam MS, Chalhoub JM, Fahed AC, Hamam RN. Ocular manifestations of severe familial hypercholesterolemia. Heliyon 2024; 10:e30487. [PMID: 38737271 PMCID: PMC11088316 DOI: 10.1016/j.heliyon.2024.e30487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/27/2024] [Accepted: 04/28/2024] [Indexed: 05/14/2024] Open
Abstract
Background To study ocular manifestations of patients with severe familial hypercholesterolemia (FH). Methods In this population-based case-control study, patients suffering from severe familial hypercholesterolemia from the Lebanese Familial Hypercholesterolemia Registry, along with age and gender-matched healthy controls were recruited. All participants underwent a comprehensive eye examination, and patients underwent fluorescein angiography as well. Logistic regression models were used to identify any association between patients with severe familial hypercholesterolemia and abnormal eye findings, while adjusting for hypertension and pack-year smoking. The main outcome measure of this study was the development of ocular vascular abnormalities. Results 28 patients and 28 controls were recruited. Patients with severe familial hypercholesterolemia had significantly greater odds of developing corneal arcus and xanthelasmas than the control group (p < 0.001). Retinal vascular abnormalities (plaques) were exclusively and more significantly present in patients with familial hypercholesterolemia (18 %). Similarly, retinal arteriosclerosis was exclusively and significantly more prevalent in the familial hypercholesterolemia group (p < 0.001, adjusted odds ratio 6.8). Stratification by LDL levels and genotypes did not show any significant change in the prevalence of any ocular finding. Conclusion In addition to the well-established increase in incidence of corneal arcus and xanthelasmas, severe familial hypercholesterolemia patients have more prevalent retinal vascular abnormalities that include vascular plaques and arteriosclerosis.
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Affiliation(s)
- Alaa Bou Ghannam
- Department of Ophthalmology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Rachid Istambouli
- Department of Ophthalmology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Mohamed S. Hamam
- Department of Ophthalmology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Jean M. Chalhoub
- Department of Ophthalmology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Akl C. Fahed
- Department of Internal Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Rola N. Hamam
- Department of Ophthalmology, American University of Beirut Medical Center, Beirut, Lebanon
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2
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Awan Z, Batran A, Al-Allaf FA, Alharbi RS, Hegazy GA, Jamalalail B, Almansouri M, Bima AI, Almukadi H, Kutbi HI, Altayar AE, Banaganapalli B, Shaik NA. Identification and functional characterization of two rare LDLR stop gain variants (p.C231* and p.R744*) in Saudi familial hypercholesterolemia patients. Panminerva Med 2023; 65:479-490. [PMID: 35274909 DOI: 10.23736/s0031-0808.22.04612-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Familial hypercholesterolemia (FH) is a globally underdiagnosed inherited metabolic disorder. Owing to limited published data from Arab world, this study was conducted with the aim of identifying the genetic and molecular basis of FH in highly consanguineous Saudi population. METHODS We performed clinical screening, biochemical profiling, whole exome sequencing and variant segregation analysis of two Saudi FH families. Additionally, 500 normolipic individuals were screened to ensure the absence of FH variant in general Saudi population. Functional characterization of FH variants on secondary structure characteristics of RNA and protein molecules was performed using different bioinformatics modelling approaches. RESULTS WES analysis identified two independent rare LDLR gene stop gain variants (p.C231* and p.R744*) consistent to the clinical presentation of FH patients from two different families. RNAfold analysis has shown that both variants were predicted to disturb the free energy dynamics of LDLR mRNA molecule and destabilize its folding pattern and function. PSIPRED based structural modelling analysis has suggested that both variants bring drastic changes disturbing the secondary structural elements of LDLR molecule. The p.C231* and p.R744* variants are responsible for partial or no protein product, thus they are class 1 variants causing loss of function (LoF) LDLR variants. CONCLUSIONS This study highlights the effectiveness of the WES, sanger sequencing, and computational analysis in expanding FH variant spectrum in culturally distinct populations like Saudi Arabia. Genetic testing of FH patients is very essential in better clinical diagnosis, screening, treatment, and management and prevention of cardiovascular disease burden in the society.
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Affiliation(s)
- Zuhier Awan
- Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Alhanuf Batran
- Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Faisal A Al-Allaf
- Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Raneem S Alharbi
- Department of Genetics, Al Borg Medical Laboratories, Jeddah, Saudi Arabia
| | - Gehan A Hegazy
- Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Bassam Jamalalail
- Department of Genetics, Al Borg Medical Laboratories, Jeddah, Saudi Arabia
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Majid Almansouri
- Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Abdulhadi I Bima
- Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Haifa Almukadi
- Department of Pharmacy Practice, Faculty of Pharmacy, King Abdulaiziz University, Jeddah, Saudi Arabia
| | - Hussam I Kutbi
- Department of Genetic Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ahmed E Altayar
- Department of Genetic Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Babajan Banaganapalli
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia
- Princess Al-Jawhara Center of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Noor A Shaik
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia -
- Princess Al-Jawhara Center of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah, Saudi Arabia
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3
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Gandhi GD, Aamer W, Krishnamoorthy N, Syed N, Aliyev E, Al-Maraghi A, Kohailan M, Alenbawi J, Elanbari M, Mifsud B, Mokrab Y, Khalil CA, Fakhro KA. Assessing the genetic burden of familial hypercholesterolemia in a large middle eastern biobank. J Transl Med 2022; 20:502. [PMID: 36329474 PMCID: PMC9635206 DOI: 10.1186/s12967-022-03697-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/29/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND The genetic architecture underlying Familial Hypercholesterolemia (FH) in Middle Eastern Arabs is yet to be fully described, and approaches to assess this from population-wide biobanks are important for public health planning and personalized medicine. METHODS We evaluate the pilot phase cohort (n = 6,140 adults) of the Qatar Biobank (QBB) for FH using the Dutch Lipid Clinic Network (DLCN) criteria, followed by an in-depth characterization of all genetic alleles in known dominant (LDLR, APOB, and PCSK9) and recessive (LDLRAP1, ABCG5, ABCG8, and LIPA) FH-causing genes derived from whole-genome sequencing (WGS). We also investigate the utility of a globally established 12-SNP polygenic risk score to predict FH individuals in this cohort with Arab ancestry. RESULTS Using DLCN criteria, we identify eight (0.1%) 'definite', 41 (0.7%) 'probable' and 334 (5.4%) 'possible' FH individuals, estimating a prevalence of 'definite or probable' FH in the Qatari cohort of ~ 1:125. We identify ten previously known pathogenic single-nucleotide variants (SNVs) and 14 putatively novel SNVs, as well as one novel copy number variant in PCSK9. Further, despite the modest sample size, we identify one homozygote for a known pathogenic variant (ABCG8, p. Gly574Arg, global MAF = 4.49E-05) associated with Sitosterolemia 2. Finally, calculation of polygenic risk scores found that individuals with 'definite or probable' FH have a significantly higher LDL-C SNP score than 'unlikely' individuals (p = 0.0003), demonstrating its utility in Arab populations. CONCLUSION We design and implement a standardized approach to phenotyping a population biobank for FH risk followed by systematically identifying known variants and assessing putative novel variants contributing to FH burden in Qatar. Our results motivate similar studies in population-level biobanks - especially those with globally under-represented ancestries - and highlight the importance of genetic screening programs for early detection and management of individuals with high FH risk in health systems.
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Affiliation(s)
- Geethanjali Devadoss Gandhi
- grid.452146.00000 0004 1789 3191College of Health and Life Sciences, Hamad Bin Khalifa University (HBKU), Doha, Qatar ,grid.467063.00000 0004 0397 4222Human Genetics Department, Sidra Medicine, Doha, Qatar
| | - Waleed Aamer
- grid.467063.00000 0004 0397 4222Human Genetics Department, Sidra Medicine, Doha, Qatar
| | | | - Najeeb Syed
- grid.467063.00000 0004 0397 4222Bioinformatics, Genomic Data Science Core, Sidra Medicine, Doha, Qatar
| | - Elbay Aliyev
- grid.467063.00000 0004 0397 4222Human Genetics Department, Sidra Medicine, Doha, Qatar
| | - Aljazi Al-Maraghi
- grid.467063.00000 0004 0397 4222Human Genetics Department, Sidra Medicine, Doha, Qatar
| | - Muhammad Kohailan
- grid.452146.00000 0004 1789 3191College of Health and Life Sciences, Hamad Bin Khalifa University (HBKU), Doha, Qatar ,grid.467063.00000 0004 0397 4222Human Genetics Department, Sidra Medicine, Doha, Qatar
| | - Jamil Alenbawi
- grid.452146.00000 0004 1789 3191College of Health and Life Sciences, Hamad Bin Khalifa University (HBKU), Doha, Qatar
| | - Mohammed Elanbari
- grid.467063.00000 0004 0397 4222Clinical Research Centre, Sidra Medicine, Doha, Qatar
| | | | - Borbala Mifsud
- grid.452146.00000 0004 1789 3191College of Health and Life Sciences, Hamad Bin Khalifa University (HBKU), Doha, Qatar
| | - Younes Mokrab
- grid.452146.00000 0004 1789 3191College of Health and Life Sciences, Hamad Bin Khalifa University (HBKU), Doha, Qatar ,grid.467063.00000 0004 0397 4222Laboratory of Medical and Population Genomics, Sidra Medicine, Doha, Qatar ,grid.416973.e0000 0004 0582 4340Department of Genetic Medicine, Weill Cornell Medicine, Education City, Qatar
| | - Charbel Abi Khalil
- grid.416973.e0000 0004 0582 4340Department of Genetic Medicine, Weill Cornell Medicine, Education City, Qatar ,grid.5386.8000000041936877XJoan and Sanford I. Weill Department of Medicine, Weill Cornell Medicine, New York, US
| | - Khalid A. Fakhro
- grid.452146.00000 0004 1789 3191College of Health and Life Sciences, Hamad Bin Khalifa University (HBKU), Doha, Qatar ,grid.467063.00000 0004 0397 4222Human Genetics Department, Sidra Medicine, Doha, Qatar ,grid.416973.e0000 0004 0582 4340Department of Genetic Medicine, Weill Cornell Medicine, Education City, Qatar
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Catalogue for Transmission Genetics in Arabs (CTGA) Database: Analysing Lebanese Data on Genetic Disorders. Genes (Basel) 2021; 12:genes12101518. [PMID: 34680914 PMCID: PMC8535931 DOI: 10.3390/genes12101518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 09/21/2021] [Accepted: 09/25/2021] [Indexed: 11/17/2022] Open
Abstract
Lebanon has a high annual incidence of birth defects at 63 per 1000 live births, most of which are due to genetic factors. The Catalogue for Transmission Genetics in Arabs (CTGA) database, currently holds data on 642 genetic diseases and 676 related genes, described in Lebanese subjects. A subset of disorders (14/642) has exclusively been described in the Lebanese population, while 24 have only been reported in CTGA and not on OMIM. An analysis of all disorders highlights a preponderance of congenital malformations, deformations and chromosomal abnormalities and demonstrates that 65% of reported disorders follow an autosomal recessive inheritance pattern. In addition, our analysis reveals that at least 58 known genetic disorders were first mapped in Lebanese families. CTGA also hosts 1316 variant records described in Lebanese subjects, 150 of which were not reported on ClinVar or dbSNP. Most variants involved substitutions, followed by deletions, duplications, as well as in-del and insertion variants. This review of genetic data from the CTGA database highlights the need for screening programs, and is, to the best of our knowledge, the most comprehensive report on the status of genetic disorders in Lebanon to date.
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5
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Kamar A, Khalil A, Nemer G. The Digenic Causality in Familial Hypercholesterolemia: Revising the Genotype-Phenotype Correlations of the Disease. Front Genet 2021; 11:572045. [PMID: 33519890 PMCID: PMC7844333 DOI: 10.3389/fgene.2020.572045] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 12/01/2020] [Indexed: 12/20/2022] Open
Abstract
Genetically inherited defects in lipoprotein metabolism affect more than 10 million individuals around the globe with preponderance in some parts where consanguinity played a major role in establishing founder mutations. Mutations in four genes have been so far linked to the dominant and recessive form of the disease. Those players encode major proteins implicated in cholesterol regulation, namely, the low-density lipoprotein receptor (LDLR) and its associate protein 1 (LDLRAP1), the proprotein convertase substilin/kexin type 9 (PCSK9), and the apolipoprotein B (APOB). Single mutations or compound mutations in one of these genes are enough to account for a spectrum of mild to severe phenotypes. However, recently several reports have identified digenic mutations in familial cases that do not necessarily reflect a much severe phenotype. Yet, data in the literature supporting this notion are still lacking. Herein, we review all the reported cases of digenic mutations focusing on the biological impact of gene dosage and the potential protective effects of single-nucleotide polymorphisms linked to hypolipidemia. We also highlight the difficulty of establishing phenotype-genotype correlations in digenic familial hypercholesterolemia cases due to the complexity and heterogeneity of the phenotypes and the still faulty in silico pathogenicity scoring system. We finally emphasize the importance of having a whole exome/genome sequencing approach for all familial cases of familial hyperlipidemia to better understand the genetic and clinical course of the disease.
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Affiliation(s)
- Amina Kamar
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Athar Khalil
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon
| | - Georges Nemer
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut, Lebanon
- Division of Genomics and Translational Biomedicine, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
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Abstract
The Middle East and North Africa regions, including Lebanon, have recently witnessed rapid urbanization and modernization over the last couple of decades that has led to a dramatic transformation affecting lifestyle and diet. The World Health Organization reports that the leading cause of death in Lebanon is due to cardiovascular disease (CVD) at 47% of all-cause mortality. Over the last 30 years, especially the last 10, the population of Lebanon has changed dramatically due to the effect of wars in the region and refugees seeking asylum. With a population of around 4.5 million and a relatively high rate of consanguinity in Lebanon, a variety of novel mutations have been discovered explaining several familial causes of hypercholesterolemia, diabetes mellitus, congenital heart disease, and cardiomyopathies. Due to the Syrian civil war, 1.5 million Syrian refugees now reside in Lebanon in either low-income housing or tented settlements. A National Institutes of Health study is examining diabetes and CVD in Syrian refugees in comparison to native Lebanese. We provide the first review of CVD in Lebanon in its metabolic component including coronary artery disease and its risk factors, mainly hyperlipidemia and diabetes mellitus, and its structural component, including congenital heart disease, valvular heart disease, cardiomyopathies, and heart failure. The knowledge in this review has been compiled to guide clinicians and assist researchers in efforts to recognize risk factors for disease, improve delivery of health care, and prevent and treat CVDs in Lebanon, both for the native Lebanese and Syrian refugees.
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7
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Mszar R, Buscher S, Taylor HL, Rice-DeFosse MT, McCann D. Familial Hypercholesterolemia and the Founder Effect Among Franco-Americans: A Brief History and Call to Action. CJC Open 2020; 2:161-167. [PMID: 32462130 PMCID: PMC7242505 DOI: 10.1016/j.cjco.2020.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 01/19/2020] [Indexed: 01/01/2023] Open
Abstract
Familial hypercholesterolemia (FH) is an inherited disorder characterized by chronically elevated low-density lipoprotein cholesterol levels and an increased risk of premature atherosclerotic cardiovascular disease. FH has been shown to disproportionately affect French Canadians and other ethnic populations due to the presence of a founder effect characterized by reduced genetic diversity resulting from relatively few individuals with FH-causing genetic mutations establishing self-contained populations. Beginning in the mid-1800s, approximately 1 million French Canadians immigrated to the Northeastern United States and largely remained in these small, tight-knit communities. Despite extensive genetic- and population-based research involving the French-Canadian founder population, primarily in the Province of Quebec, little is known regarding Franco-Americans in the United States. Concurrent with addressing the underdiagnosis rate of FH in the general population, we propose the following steps to leverage this founder effect and meet the cardiovascular needs of Franco-Americans: (1) increase cascade screening in regions of the United States with a high proportion of individuals of French-Canadian descent; (2) promote registry-based, epidemiological research to elucidate accurate prevalence estimates as well as diagnostic and treatment gaps in Franco-Americans; and (3) validate contemporary risk stratification strategies such as the Montreal-FH-SCORE to enable optimal lipid management and prevention of premature atherosclerotic cardiovascular disease among French-Canadian descendants.
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Affiliation(s)
- Reed Mszar
- Department of Chronic Disease Epidemiology, Yale School of Public Health, New Haven, Connecticut, USA
| | - Sara Buscher
- Division of General Pediatrics, Boston Children’s Hospital, Boston, Massachusetts
| | - Heidi L. Taylor
- Department of Sociology, Bates College, Lewiston, Maine, USA
| | - Mary T. Rice-DeFosse
- Department of French and Francophone Studies, Bates College, Lewiston, Maine, USA
| | - Dervilla McCann
- Department of Cardiology, Central Maine Medical Center, Lewiston, Maine, USA
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8
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Kolovou GD, Watts GF, Mikhailidis DP, Pérez-Martínez P, Mora S, Bilianou H, Panotopoulos G, Katsiki N, Ooi TC, Lopez-Miranda J, Tybjærg-Hansen A, Tentolouris N, Nordestgaard BG. Postprandial Hypertriglyceridaemia Revisited in the Era of Non-Fasting Lipid Profile Testing: A 2019 Expert Panel Statement, Narrative Review. Curr Vasc Pharmacol 2019; 17:515-537. [DOI: 10.2174/1570161117666190503123911] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/01/2019] [Accepted: 04/11/2019] [Indexed: 12/17/2022]
Abstract
Postprandial hypertriglyceridaemia, defined as an increase in plasma triglyceride-containing
lipoproteins following a fat meal, is a potential risk predictor of atherosclerotic cardiovascular disease
and other chronic diseases. Several non-modifiable factors (genetics, age, sex and menopausal status)
and lifestyle factors (diet, physical activity, smoking status, obesity, alcohol and medication use) may
influence postprandial hypertriglyceridaemia. This narrative review considers the studies published over
the last decade that evaluated postprandial hypertriglyceridaemia. Additionally, the genetic determinants
of postprandial plasma triglyceride levels, the types of meals for studying postprandial triglyceride response,
and underlying conditions (e.g. familial dyslipidaemias, diabetes mellitus, metabolic syndrome,
non-alcoholic fatty liver and chronic kidney disease) that are associated with postprandial hypertriglyceridaemia
are reviewed; therapeutic aspects are also considered.
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Affiliation(s)
- Genovefa D. Kolovou
- Cardiology Department and LDL-Apheresis Unit, Onassis Cardiac Surgery Center, Athens, Greece
| | - Gerald F. Watts
- Lipid Disorders Clinic, Department of Cardiology, Royal Perth Hospital, School of Medicine, Faculty of Health and Medical Sciences, University of Western Australia, Crawley, Australia
| | - Dimitri P. Mikhailidis
- Department of Clinical Biochemistry, Royal Free Hospital Campus, University College London Medical School, University College London (UCL), London, United Kingdom
| | - Pablo Pérez-Martínez
- Lipid and Atherosclerosis Unit, IMIBIC/Reina Sofia University Hospital/University of Cordoba, and CIBER Fisiopatologia Obesidad y Nutricion (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Samia Mora
- Center for Lipid Metabolomics, Divisions of Preventive and Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Helen Bilianou
- Department of Cardiology, Tzanio Hospital, Piraeus, Greece
| | | | - Niki Katsiki
- First Department of Internal Medicine, Division of Endocrinology-Metabolism, Diabetes Center, AHEPA University Hospital, Thessaloniki, Greece
| | - Teik C. Ooi
- Department of Medicine, Division of Endocrinology and Metabolism, University of Ottawa, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - José Lopez-Miranda
- Lipid and Atherosclerosis Unit, IMIBIC/Reina Sofia University Hospital/University of Cordoba, and CIBER Fisiopatologia Obesidad y Nutricion (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Anne Tybjærg-Hansen
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen University Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicholas Tentolouris
- First Department of Propaedeutic Internal Medicine, Medical School, National and Kapodistrian University of Athens, Laiko General Hospital, Athens, Greece
| | - Børge G. Nordestgaard
- Department of Clinical Biochemistry, Herlev and Gentofte Hospital, Copenhagen University Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Mohd Nor NS, Al-Khateeb AM, Chua YA, Mohd Kasim NA, Mohd Nawawi H. Heterozygous familial hypercholesterolaemia in a pair of identical twins: a case report and updated review. BMC Pediatr 2019; 19:106. [PMID: 30975109 PMCID: PMC6458607 DOI: 10.1186/s12887-019-1474-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 03/28/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Familial hypercholesterolaemia (FH) is the most common inherited metabolic disease with an autosomal dominant mode of inheritance. It is characterised by raised serum levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-c), leading to premature coronary artery disease. Children with FH are subjected to early and enhanced atherosclerosis, leading to greater risk of coronary events, including premature coronary artery disease. To the best of our knowledge, this is the first report of a pair of monochorionic diamniotic identical twins with a diagnosis of heterozygous FH, resulting from mutations in both LDLR and ABCG8 genes. CASE PRESENTATION This is a rare case of a pair of 8-year-old monochorionic diamniotic identical twin, who on family cascade screening were diagnosed as definite FH, according to the Dutch Lipid Clinic Criteria (DLCC) with a score of 10. There were no lipid stigmata noted. Baseline lipid profiles revealed severe hypercholesterolaemia, (TC = 10.5 mmol/L, 10.6 mmol/L; LDL-c = 8.8 mmol/L, 8.6 mmol/L respectively). Their father is the index case who initially presented with premature CAD, and subsequently diagnosed as FH. Family cascade screening identified clinical FH in other family members including their paternal grandfather who also had premature CAD, and another elder brother, aged 10 years. Genetic analysis by targeted next-generation sequencing using MiSeq platform (Illumina) was performed to detect mutations in LDLR, APOB100, PCSK9, ABCG5, ABCG8, APOE and LDLRAP1 genes. Results revealed that the twin, their elder brother, father and grandfather are heterozygous for a missense mutation (c.530C > T) in LDLR that was previously reported as a pathogenic mutation. In addition, the twin has heterozygous ABCG8 gene mutation (c.55G > C). Their eldest brother aged 12 years and their mother both had normal lipid profiles with absence of LDLR gene mutation. CONCLUSION A rare case of Asian monochorionic diamniotic identical twin, with clinically diagnosed and molecularly confirmed heterozygous FH, due to LDLR and ABCG8 gene mutations have been reported. Childhood FH may not present with the classical physical manifestations including the pathognomonic lipid stigmata as in adults. Therefore, childhood FH can be diagnosed early using a combination of clinical criteria and molecular analyses.
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Affiliation(s)
- Noor Shafina Mohd Nor
- Institute for Pathology, Laboratory and Forensic Medicine (I-PPerForM), Universiti Teknologi MARA (UiTM), Sungai Buloh Campus, Jalan Hospital, 47000, Sungai Buloh, Selangor, Malaysia.,Departments of Paediatric, Biochemistry and Chemical Pathology, Faculty of Medicine, Universiti Teknologi MARA (UiTM), 47000, Sungai Buloh, Selangor, Malaysia
| | - Alyaa Mahmood Al-Khateeb
- Institute for Pathology, Laboratory and Forensic Medicine (I-PPerForM), Universiti Teknologi MARA (UiTM), Sungai Buloh Campus, Jalan Hospital, 47000, Sungai Buloh, Selangor, Malaysia.,Departments of Paediatric, Biochemistry and Chemical Pathology, Faculty of Medicine, Universiti Teknologi MARA (UiTM), 47000, Sungai Buloh, Selangor, Malaysia
| | - Yung-An Chua
- Institute for Pathology, Laboratory and Forensic Medicine (I-PPerForM), Universiti Teknologi MARA (UiTM), Sungai Buloh Campus, Jalan Hospital, 47000, Sungai Buloh, Selangor, Malaysia
| | - Noor Alicezah Mohd Kasim
- Institute for Pathology, Laboratory and Forensic Medicine (I-PPerForM), Universiti Teknologi MARA (UiTM), Sungai Buloh Campus, Jalan Hospital, 47000, Sungai Buloh, Selangor, Malaysia.,Departments of Paediatric, Biochemistry and Chemical Pathology, Faculty of Medicine, Universiti Teknologi MARA (UiTM), 47000, Sungai Buloh, Selangor, Malaysia
| | - Hapizah Mohd Nawawi
- Institute for Pathology, Laboratory and Forensic Medicine (I-PPerForM), Universiti Teknologi MARA (UiTM), Sungai Buloh Campus, Jalan Hospital, 47000, Sungai Buloh, Selangor, Malaysia. .,Departments of Paediatric, Biochemistry and Chemical Pathology, Faculty of Medicine, Universiti Teknologi MARA (UiTM), 47000, Sungai Buloh, Selangor, Malaysia.
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Alhababi D, Zayed H. Spectrum of mutations of familial hypercholesterolemia in the 22 Arab countries. Atherosclerosis 2018; 279:62-72. [PMID: 30415195 DOI: 10.1016/j.atherosclerosis.2018.10.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 10/15/2018] [Accepted: 10/18/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND AIMS Familial hypercholesterolemia (FH) is an inherited genetic disorder of lipid metabolism characterized by a high serum LDL-cholesterol profile and xanthoma formation, and FH increases the risk of premature atherosclerosis and cardiovascular disease (CVD). Mutations in the low-density lipoprotein (LDLR), apolipoprotein B (APOB), proprotein convertase subtilisin/kexin 9 (PCSK9), and LDLRAP1 genes have been associated with FH. Although FH is a major risk for CVD, the disease prevalence and its underlying molecular basis in the 22 Arab countries are still understudied. This study aimed to analyze all peer-reviewed studies related to the prevalence of FH and its causative mutations in the 22 Arab countries. METHODS We searched five literature databases (Scopus, Science Direct, Web of Science, PubMed, and Google Scholar) from inception until June 2018, using all possible search terms to capture all of the genetic and prevalence data related to Arab patients with FH. RESULTS A total of 5,484 titles and abstracts were identified; 51 studies met our inclusion criteria for the final systematic review. Fifty-one mutations in Arab patients with FH were identified in only eight Arab countries; 47 were identified in the LDLR gene, two in the PCSK9 gene, and two in LDLRAP1 gene. Twenty mutations in the LDLR gene were distinctive to Arab patients. A few studies reported prevalence estimates, ranging from 0.4% to 6.8%. CONCLUSIONS This is the first systematic review to dissect the up-to-date status of the genetic epidemiology of Arab patients with FH. It seems that FH is underdiagnosed and that its prevalence is understudied due to the dearth of published information about Arab patients with FH. Therefore, there is a need for well-controlled genetic epidemiological studies on Arab patients with FH.
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Affiliation(s)
- Dalal Alhababi
- College of Health Sciences, Biomedical Program, Qatar University, Doha, Qatar
| | - Hatem Zayed
- College of Health Sciences, Biomedical Program, Qatar University, Doha, Qatar.
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11
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Alallaf F, H.Nazar FA, Alnefaie M, Almaymuni A, Rashidi OM, Alhabib K, Alnouri F, Alama MN, Athar M, Awan Z. The Spectrum of Familial Hypercholesterolemia (FH) in Saudi Arabia: Prime Time for Patient FH Registry. Open Cardiovasc Med J 2017; 11:66-75. [PMID: 28868092 PMCID: PMC5564019 DOI: 10.2174/1874192401711010066] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 04/27/2017] [Accepted: 05/17/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Familial hypercholesterolemia (FH) is a life-threatening inherited condition. Untreated patients have the risk to develop raised plasma levels of cholesterol, atherosclerosis and cardiovascular disease (CVD). If diagnosed and treated early in life, the pathological consequences due to atherosclerosis could be avoided and patients with FH can have an anticipated normal life. Mounting evidence suggests that FH is underdiagnosed and undertreated in all populations. The underlying molecular basis of FH is the presence of mutations in one or more genes in the low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB) or proprotein convertase subtilisin/kexin 9 (PCSK9). However, their prevalence is largely unknown in Saudi Arabia but given the high rates of consanguinity, the prevalence appears to be higher. Furthermore, the high prevalence of obesity and diabetes mellitus in Saudi Arabia increases the vascular disease burden in FH cases by adding additional CVD risk factors. OBJECTIVE This article explores the spectrum of FH-causing mutations in the highly consanguineous Saudi community, the need for establishing the Saudi FH registry, the challenges in creating gene databases, and cascade screening. CONCLUSION The establishment of FH registry and genetic testing should raise awareness not only among healthcare professionals, but the general population as well. It also helps to provide the best treatment regimen in a cost effective manner to this under-recognised population of FH patients.
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Affiliation(s)
- Faisal Alallaf
- Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Mekkah. Saudi Arabia
| | - Fatima Amanullah H.Nazar
- Department of Biology, Genomic and Biotechnology Section, Faculty of Science, King Abdulaziz University, Jeddah. Saudi Arabia
| | - Majed Alnefaie
- Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah. Saudi Arabia
| | - Adel Almaymuni
- Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah. Saudi Arabia
| | - Omran Mohammed Rashidi
- Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah. Saudi Arabia
| | - Khalid Alhabib
- Interventional Cardiology, King Fahad Cardiac Center, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Fahad Alnouri
- Cardiovascular Prevention and Rehabilitation Unit, Prince Sultan Cardiac Centre, Riyadh, Saudi Arabia
| | - Mohamed-Nabil Alama
- Adult interventional cardiology, Cardiology unit, King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia
| | - Mohammad Athar
- Department of Science and Technology, Umm Al-Qura University, Mekkah, Saudi Arabia
| | - Zuhier Awan
- Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah. Saudi Arabia
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12
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Premature Valvular Heart Disease in Homozygous Familial Hypercholesterolemia. CHOLESTEROL 2017; 2017:3685265. [PMID: 28761763 PMCID: PMC5518507 DOI: 10.1155/2017/3685265] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 04/18/2017] [Accepted: 05/29/2017] [Indexed: 11/17/2022]
Abstract
Valvular heart disease frequently occurs as a consequence of premature atherosclerosis in individuals with familial hypercholesterolemia (FH). Studies have primarily focused on aortic valve calcification in heterozygous FH, but there is paucity of data on the incidence of valvular disease in homozygous FH. We performed echocardiographic studies in 33 relatively young patients (mean age: 26 years) with homozygous FH (mean LDL of 447 mg/dL, 73% on LDL apheresis) to look for subclinical valvulopathy. Twenty-one patients had evidence of valvulopathy of the aortic or mitral valves, while seven subjects showed notable mitral regurgitation. Older patients were more likely to have aortic valve calcification (>21 versus ≤21 years: 59% versus 12.5%; p = 0.01) despite lower LDL levels at the time of the study (385 versus 513 mg/dL; p = 0.016). Patients with valvulopathy were older and had comparable LDL levels and a lower carotid intima-media thickness. Our data suggests that, in homozygous FH patients, valvulopathy (1) is present across a wide age spectrum and LDL levels and (2) is less likely to be influenced by lipid-lowering treatment. Echocardiographic studies that focused on aortic root thickening and stenosis and regurgitation are thus likely an effective modality for serial follow-up of subclinical valvular heart disease.
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13
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Andary R, El-Hage-Sleiman AK, Farhat T, Sanjad S, Nemer G. Hereditary vitamin D-resistant rickets in Lebanese patients: the p.R391S and p.H397P variants have different phenotypes. J Pediatr Endocrinol Metab 2017; 30:437-444. [PMID: 28301319 DOI: 10.1515/jpem-2016-0338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 01/31/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND Hereditary vitamin D-resistant rickets (HVDRR) is an autosomal recessive disorder caused by mutations in the vitamin D receptor (VDR) gene. Variable phenotypes have been associated with these mutations, and some of these were linked to the effects they have on the interacting partners of VDR, mainly the retinoic X receptor (RXR). METHODS We examined four patients with HVDRR from three unrelated Lebanese families. All parents were consanguineous with normal phenotype. We used Sanger sequencing to identify mutations in the coding exons of VDR. RESULTS Two homozygous mutations (p.R391S and p.H397P), both in exon 9 of the VDR gene, were identified. Phenotype/genotype association was not possible even for the same mutation. Alopecia was seen only with the p.R391S mutation. Despite a comparable rachitic bone disease, the patients showed different responsiveness to large doses of alfacalcidol (1-α-hydroxy vitamin D3) supplementation. CONCLUSIONS This is the first report of VDR mutations in Lebanon with promising clinical outcomes despite the severity of the phenotypes.
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Affiliation(s)
- Rabih Andary
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut
| | | | - Theresa Farhat
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut
| | - Sami Sanjad
- Department of Pediatrics and Adolescent Medicine, American University of Beirut, Bliss Street, Beirut
| | - Georges Nemer
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Bliss Street P.O. Box 11-0236, Beirut
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14
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Sánchez-Hernández RM, Civeira F, Stef M, Perez-Calahorra S, Almagro F, Plana N, Novoa FJ, Sáenz-Aranzubía P, Mosquera D, Soler C, Fuentes FJ, Brito-Casillas Y, Real JT, Blanco-Vaca F, Ascaso JF, Pocovi M. Homozygous Familial Hypercholesterolemia in Spain. ACTA ACUST UNITED AC 2016; 9:504-510. [DOI: 10.1161/circgenetics.116.001545] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 09/28/2016] [Indexed: 11/16/2022]
Abstract
Background—
Homozygous familial hypercholesterolemia (HoFH) is a rare disease characterized by elevated plasma levels of low-density lipoprotein cholesterol (LDL-C) and extremely high risk of premature atherosclerotic cardiovascular disease. HoFH is caused by mutations in several genes, including LDL receptor (
LDLR
), apolipoprotein B (
APOB
), proprotein convertase subtilisin/kexin type 9 (
PCSK9
), and LDL protein receptor adaptor 1 (
LDLRAP1
). No epidemiological studies have assessed HoFH prevalence or the clinical and molecular characteristics of this condition. Here, we aimed to characterize HoFH in Spain.
Methods and Results—
Data were collected from the Spanish Dyslipidemia Registry of the Spanish Atherosclerosis Society and from all molecular diagnoses performed for familial hypercholesterolemia in Spain between 1996 and 2015 (n=16 751). Clinical data included baseline lipid levels and atherosclerotic cardiovascular disease events. A total of 97 subjects were identified as having HoFH—of whom, 47 were true homozygous (1 for
APOB
, 5 for
LDLRAP1
, and 41 for
LDLR
), 45 compound heterozygous for
LDLR
, 3 double heterozygous for
LDLR
and
PSCK9
, and 2 double heterozygous for
LDLR
and
APOB
. No
PSCK9
homozygous cases were identified. Two variants in
LDLR
were identified in 4.8% of the molecular studies. Over 50% of patients did not meet the classical HoFH diagnosis criteria. The estimated HoFH prevalence was 1:450 000. Compared with compound heterozygous cases, true homozygous cases showed more aggressive phenotypes with higher LDL-C and more atherosclerotic cardiovascular disease events.
Conclusions—
HoFH frequency in Spain was higher than expected. Clinical criteria would underestimate the actual prevalence of individuals with genetic HoFH, highlighting the importance of genetic analysis to improve familial hypercholesterolemia diagnosis accuracy.
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15
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Al Sayed N, Al Waili K, Alawadi F, Al-Ghamdi S, Al Mahmeed W, Al-Nouri F, Al Rukhaimi M, Al-Rasadi K, Awan Z, Farghaly M, Hassanein M, Sabbour H, Zubaid M, Barter P. Consensus clinical recommendations for the management of plasma lipid disorders in the Middle East. Int J Cardiol 2016; 225:268-283. [PMID: 27741487 DOI: 10.1016/j.ijcard.2016.09.081] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 09/22/2016] [Accepted: 09/23/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND Plasma lipid disorders are key risk factors for the development of atherosclerotic cardiovascular disease (ASCVD) and are prevalent in the Middle East, with rates increasing in recent decades. Despite this, no region-specific guidelines for managing plasma lipids exist and there is a lack of use of guidelines developed in other regions. METHODS A multidisciplinary panel of regional experts was convened to develop consensus clinical recommendations for the management of plasma lipids in the Middle East. The panel considered existing international guidelines and regional clinical experience to develop recommendations. RESULTS The panel's recommendations include plasma lipid screening, ASCVD risk calculation and treatment considerations. The panel recommend that plasma lipid levels should be measured in all at-risk patients and at regular intervals in all adults from the age of 20years. A scoring system should be used to calculate ASCVD risk that includes known lipid and non-lipid risk factors. Primary treatment targets include low-density lipoprotein cholesterol and non-high-density lipoprotein cholesterol. Lifestyle modifications should be first-line treatment for all patients; the first-line pharmacological treatment targeting plasma lipids in patients at moderate-to-high risk of ASCVD is statin therapy, with a number of adjunctive or second-line agents available. Guidance is also provided on the management of underlying conditions and special populations; of particular pertinence in the region are familial hypercholesterolaemia, diabetes and metabolic dyslipidaemia. CONCLUSIONS These consensus clinical recommendations provide practicing clinicians with comprehensive, region-specific guidance to improve the detection and management of plasma lipid disorders in patients in the Middle East.
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Affiliation(s)
- Nasreen Al Sayed
- Gulf Diabetes Specialist Center, P.O. Box 21686, Manama, Bahrain.
| | - Khalid Al Waili
- Department of Clinical Biochemistry, Sultan Qaboos University Hospital, Al-Khod, P.O. Box 38, postal code 123, Muscat, Oman.
| | - Fatheya Alawadi
- Endocrine Department, Dubai Hospital, Dubai Health Authority, Dubai, United Arab Emirates.
| | - Saeed Al-Ghamdi
- Department of Medicine, King Abdulaziz University Hospital, P.O. Box 80215, Jeddah 21589, Saudi Arabia.
| | - Wael Al Mahmeed
- Heart and Vascular Institute, Cleveland Clinic, Abu Dhabi, United Arab Emirates.
| | - Fahad Al-Nouri
- Cardiovascular Prevention Unit, Prince Sultan Cardiac Center, Riyadh, Saudi Arabia.
| | - Mona Al Rukhaimi
- Dubai Medical College, P.O. Box 22331, Dubai, United Arab Emirates.
| | - Khalid Al-Rasadi
- Department of Biochemistry, Sultan Qaboos University Hospital, Al-Khod, P.O. Box 38, postal code 123, Muscat, Oman.
| | - Zuhier Awan
- King Abdulaziz University, Jeddah 22254, Saudi Arabia.
| | | | | | - Hani Sabbour
- Shaikh Khalifa Medical City, Cardiac Sciences Institute, Abu Dhabi, United Arab Emirates.
| | - Mohammad Zubaid
- Department of Medicine, Faculty of Medicine, Kuwait University, Kuwait.
| | - Philip Barter
- School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
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16
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Fahed AC, Khalaf R, Salloum R, Andary RR, Safa R, El-Rassy I, Moubarak E, Azar ST, Bitar FF, Nemer G. Variable expressivity and co-occurrence of LDLR and LDLRAP1 mutations in familial hypercholesterolemia: failure of the dominant and recessive dichotomy. Mol Genet Genomic Med 2016; 4:283-91. [PMID: 27247956 PMCID: PMC4867562 DOI: 10.1002/mgg3.203] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 12/14/2015] [Accepted: 12/17/2015] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND The familial inherited genetic disorder of lipoprotein metabolism affects more than 10 million individuals around the world. Lebanon is one of the several endemic areas for familial hypercholesterolemia (FH) with a founder mutation in the low-density lipoprotein cholesterol receptor (LDLR) gene, responsible for most of the cases. We have previously shown that 16% of all familial cases with hypercholesterolemia do not show genotype segregation of LDLR with the underlying phenotype. METHODS We used Sanger sequencing to genotype 25 Lebanese families with severe FH for the gene encoding the LDLR-associated protein (LDLRAP1), responsible for the recessive form of the disease starting with the four families that did not show any genotype-phenotype correlation in our previous screening. RESULTS We showed that the previously reported p.Q136* variant is linked to the hypercholesterolemia phenotype in the four families. In addition, we showed a variable phenotype between families and between members of the same family. One family exhibits mutations in both LDLR and LDLRAP1 with family members showing differential phenotypes unexplained by the underlying genotypes of the two genes. CONCLUSION The p.Q136* variant in LDLRAP1 is yet another founder mutation in Lebanon and coupled with the LDLR p.C681* variant explains all the genetic causes of FH in Lebanon.
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Affiliation(s)
- Akl C Fahed
- Department of Biochemistry and Molecular GeneticsAmerican University of BeirutBeirutLebanon; Department of GeneticsHarvard Medical School and Department of Internal MedicineMassachusetts General HospitalBostonMassachusetts
| | - Ruby Khalaf
- Department of Biochemistry and Molecular Genetics American University of Beirut Beirut Lebanon
| | - Rony Salloum
- Department of Biochemistry and Molecular Genetics American University of Beirut Beirut Lebanon
| | - Rabih R Andary
- Department of Biochemistry and Molecular Genetics American University of Beirut Beirut Lebanon
| | - Raya Safa
- Department of Biochemistry and Molecular Genetics American University of Beirut Beirut Lebanon
| | - Inaam El-Rassy
- Department of Biochemistry and Molecular Genetics American University of Beirut Beirut Lebanon
| | - Elie Moubarak
- National LDL Apheresis Center Dahr El-Bashek Governmental University Hospital Roumieh Lebanon
| | - Sami T Azar
- Department of Internal Medicine American University of Beirut Beirut Lebanon
| | - Fadi F Bitar
- Department of Pediatrics and Adolescent Medicine American University of Beirut Beirut Lebanon
| | - Georges Nemer
- Department of Biochemistry and Molecular Genetics American University of Beirut Beirut Lebanon
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17
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Zhou M, Zhao D. Familial Hypercholesterolemia in Asian Populations. J Atheroscler Thromb 2016; 23:539-49. [DOI: 10.5551/jat.34405] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Mengge Zhou
- Department of Epidemiology, Beijing An Zhen Hospital, Capital Medical University, the Key Laboratory of Remodeling-Related Cardiovascular Diseases, Ministry of Education, Beijing Institute of Heart, Lung and Blood Vessel Diseases
| | - Dong Zhao
- Department of Epidemiology, Beijing An Zhen Hospital, Capital Medical University, the Key Laboratory of Remodeling-Related Cardiovascular Diseases, Ministry of Education, Beijing Institute of Heart, Lung and Blood Vessel Diseases
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18
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Al-Allaf FA, Alashwal A, Abduljaleel Z, Taher MM, Siddiqui SS, Bouazzaoui A, Abalkhail H, Aun R, Al-Allaf AF, AbuMansour I, Azhar Z, Ba-Hammam FA, Khan W, Athar M. Identification of a recurrent frameshift mutation at the LDLR exon 14 (c.2027delG, p.(G676Afs*33)) causing familial hypercholesterolemia in Saudi Arab homozygous children. Genomics 2015; 107:24-32. [PMID: 26688439 DOI: 10.1016/j.ygeno.2015.12.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/06/2015] [Accepted: 12/09/2015] [Indexed: 11/25/2022]
Abstract
Familial hypercholesterolemia (FH) is an autosomal dominant disease, predominantly caused by variants in the low-density lipoprotein (LDL) receptor gene (LDLR). Herein, we describe genetic analysis of severely affected homozygous FH patients who were mostly resistant to statin therapy and were managed on an apheresis program. We identified a recurrent frameshift mutation p.(G676Afs*33) in exon 14 of the LDLR gene in 9 probands and their relatives in an apparently unrelated Saudi families. We also describe a three dimensional homology model of the LDL receptor protein (LDLR) structure and examine the consequence of the frameshift mutation p.(G676Afs*33), as this could affect the LDLR structure in a region involved in dimer formation, and protein stability. This finding of a recurrent mutation causing FH in the Saudi population could serve to develop a rapid genetic screening procedure for FH, and the 3D-structure analysis of the mutant LDLR, may provide tools to develop a mechanistic model of the LDLR function.
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Affiliation(s)
- Faisal A Al-Allaf
- Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia; Science and Technology Unit, Umm Al-Qura University, Makkah, Saudi Arabia; Molecular Diagnostics Unit, Department of Laboratory and Blood Bank, King Abdullah Medical City, Makkah, Saudi Arabia.
| | - Abdullah Alashwal
- King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Zainularifeen Abduljaleel
- Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia; Science and Technology Unit, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Mohiuddin M Taher
- Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia; Science and Technology Unit, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Shahid S Siddiqui
- Department of Oral and Basic Sciences, Faculty of Dentistry, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Abdellatif Bouazzaoui
- Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia; Science and Technology Unit, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Hala Abalkhail
- King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Rakan Aun
- Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia
| | | | - Iman AbuMansour
- Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Zohor Azhar
- Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Faisal A Ba-Hammam
- Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Wajahatullah Khan
- Department of Basic Sciences, College of Science and Health Professions, King Saud Bin Abdul Aziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Mohammad Athar
- Department of Medical Genetics, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia; Science and Technology Unit, Umm Al-Qura University, Makkah, Saudi Arabia.
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19
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Brautbar A, Leary E, Rasmussen K, Wilson DP, Steiner RD, Virani S. Genetics of familial hypercholesterolemia. Curr Atheroscler Rep 2015; 17:491. [PMID: 25712136 DOI: 10.1007/s11883-015-0491-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Familial hypercholesterolemia (FH) is a genetic disorder characterized by elevated low-density lipoprotein (LDL) cholesterol and premature cardiovascular disease, with a prevalence of approximately 1 in 200-500 for heterozygotes in North America and Europe. Monogenic FH is largely attributed to mutations in the LDLR, APOB, and PCSK9 genes. Differential diagnosis is critical to distinguish FH from conditions with phenotypically similar presentations to ensure appropriate therapeutic management and genetic counseling. Accurate diagnosis requires careful phenotyping based on clinical and biochemical presentation, validated by genetic testing. Recent investigations to discover additional genetic loci associated with extreme hypercholesterolemia using known FH families and population studies have met with limited success. Here, we provide a brief overview of the genetic determinants, differential diagnosis, genetic testing, and counseling of FH genetics.
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Affiliation(s)
- Ariel Brautbar
- Division of Genetics, Cook Children's Medical Center, Fort Worth, TX, USA,
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20
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Deek H, Newton P, Inglis S, Kabbani S, Noureddine S, Macdonald PS, Davidson PM. Heart health in Lebanon and considerations for addressing the burden of cardiovascular disease. Collegian 2015; 22:333-9. [DOI: 10.1016/j.colegn.2014.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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21
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Sjouke B, Hovingh GK, Kastelein JJP, Stefanutti C. Homozygous autosomal dominant hypercholesterolaemia: prevalence, diagnosis, and current and future treatment perspectives. Curr Opin Lipidol 2015; 26:200-9. [PMID: 25950706 DOI: 10.1097/mol.0000000000000179] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
PURPOSE OF REVIEW Homozygous autosomal dominant hypercholesterolemia (hoADH) is a rare genetic disorder caused by mutations in LDL receptor, apolipoprotein B, and/or proprotein convertase subtilisin-kexin type 9. Both the genetic mutations and the clinical phenotype vary largely among individual patients, but patients with hoADH are typically characterized by extremely elevated LDL-cholesterol (LDL-C) levels, and a very high-risk for premature cardiovascular disease. Current lipid-lowering therapies include bile acid sequestrants, statins, and ezetimibe. To further decrease LDL-C levels in hoADH, lipoprotein apheresis is recommended, but this therapy is not available in all countries. RECENT FINDINGS Recently, the microsomal triglyceride transfer protein inhibitor lomitapide and the RNA antisense inhibitor of apolipoprotein B mipomersen were approved by the Food and Drug Administration/European Medicine Agency and the Food and Drug Administration, respectively. Several other LDL-C-lowering strategies and therapeutics targeting the HDL-C pathway are currently in the clinical stage of development. SUMMARY Novel therapies have been introduced for LDL-C-lowering and innovative drug candidates for HDL-C modulation for the treatment of hoADH. Here, we review the current available literature on the prevalence, diagnosis, and therapeutic strategies for hoADH.
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Affiliation(s)
- Barbara Sjouke
- aDepartment of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands bDepartment of Molecular Medicine, Extracorporeal Therapeutic Techniques Unit - Lipid Clinic and Atherosclerosis Prevention Centre, 'Sapienza' University of Rome, Rome, Italy
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22
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AlBacha JD, Khoury M, Mouawad C, Haddad K, Hamoui S, Azar A, Fajloun Z, Makdissy N. High Incidence of ACE/PAI-1 in Association to a Spectrum of Other Polymorphic Cardiovascular Genes Involving PBMCs Proinflammatory Cytokines in Hypertensive Hypercholesterolemic Patients: Reversibility with a Combination of ACE Inhibitor and Statin. PLoS One 2015; 10:e0127266. [PMID: 25973747 PMCID: PMC4431854 DOI: 10.1371/journal.pone.0127266] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 04/13/2015] [Indexed: 11/18/2022] Open
Abstract
Cardiovascular diseases (CVDs) are significantly high in the Lebanese population with the two most predominant forms being atherosclerosis and venous thrombosis. The purpose of our study was to assess the association of a spectrum of CVD related genes and combined state of hypertension hypercholesterolemia (HH) in unrelated Lebanese. Twelve polymorphisms were studied by multiplex PCR and reverse hybridization of DNA from 171 healthy individuals and 144 HH subjects. Two genes were significantly associated with HH: ACE (OR: 9.20, P<0.0001) and PAI-1 (OR: 2.29, P = 0.007), respectively with the occurrence of the risky alleles “Del” and “4G”. The frequencies of the Del and 4G alleles were found to be 0.98 and 0.90 in the HH group versus 0.84 and 0.79 in the healthy group, respectively. Serum ACE activity and PAI-I increased significantly with Del/Del and 4G/5G genotypes. The co-expression of Del/4G(+/+) was detected in 113 out of 171 (66.0%) controls and 125 out of 144 (86.8%) HH subjects. Del/4G(-/-) was detected in only 6 (3.5%) controls and undetected in the HH group. Three venous thrombosis related genes [FV(Leiden), MTHFR(A1298C) and FXIII(V34L)] were significantly related to the prominence of the co-expression of Del/4G(+/+). A range of 2 to 8 combined polymorphisms co-expressed per subject where 5 mutations were the most detected. In Del/4G(+/+) subjects, peripheral blood mononuclear cells (PBMCs) produced significant elevated levels of IFN-γ and TNF-α contrary to IL-10, and no variations occurred for IL-4. ACE inhibitor (ramipril) in combination with statin (atorvastatin) and not alone reversed significantly the situation. This first report from Lebanon sheds light on an additional genetic predisposition of a complex spectrum of genes involved in CVD and suggests that the most requested gene FVL by physicians may not be sufficient to diagnose eventual future problems that can occur in the cardiovascular system. Subjects expressing the double mutations (Del/4G) are at high risk for the onset of CVDs.
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Affiliation(s)
- Jeanne d’Arc AlBacha
- Reviva Regenerative Medicine Center, Human Genetic Center, Middle East Institute of Health Hospital, Bsalim, Lebanon
- Laboratory of Applied Biotechnology, Azm Center for the Research in Biotechnology and its Applications, Doctoral School for Sciences and Technology, Lebanese University, Tripoli, Lebanon
| | - Mira Khoury
- Reviva Regenerative Medicine Center, Human Genetic Center, Middle East Institute of Health Hospital, Bsalim, Lebanon
| | - Charbel Mouawad
- Department of Biology, Faculty of Science, Section III, Lebanese University, El Kobeh, Lebanon
| | - Katia Haddad
- Department of Biology, Faculty of Science, Section III, Lebanese University, El Kobeh, Lebanon
| | - Samar Hamoui
- Department of Biology, Faculty of Science, Section III, Lebanese University, El Kobeh, Lebanon
| | - Albert Azar
- Reviva Regenerative Medicine Center, Human Genetic Center, Middle East Institute of Health Hospital, Bsalim, Lebanon
| | - Ziad Fajloun
- Reviva Regenerative Medicine Center, Human Genetic Center, Middle East Institute of Health Hospital, Bsalim, Lebanon
- Laboratory of Applied Biotechnology, Azm Center for the Research in Biotechnology and its Applications, Doctoral School for Sciences and Technology, Lebanese University, Tripoli, Lebanon
| | - Nehman Makdissy
- Reviva Regenerative Medicine Center, Human Genetic Center, Middle East Institute of Health Hospital, Bsalim, Lebanon
- Department of Biology, Faculty of Science, Section III, Lebanese University, El Kobeh, Lebanon
- * E-mail:
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NKX2-5 mutations in an inbred consanguineous population: genetic and phenotypic diversity. Sci Rep 2015; 5:8848. [PMID: 25742962 DOI: 10.1038/srep08848] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 01/14/2015] [Indexed: 11/08/2022] Open
Abstract
NKX2-5 mutations are associated with different forms of congenital heart disease. Despite the knowledge gained from molecular and animal studies, genotype-phenotype correlations in humans are limited by the lack of large cohorts and the incomplete assessment of family members. We hypothesized that studying the role of NKX2-5 in inbred populations with homogeneous genetic backgrounds and high consanguinity rates such as Lebanon could help closing this gap. We sequenced NKX2-5 in 188 index CHD cases (25 with ASD). Five variants (three segregated in families) were detected in eleven families including the previously documented p.R25C variant, which was found in seven patients from different families, and in one healthy individual. In 3/5 familial dominant ASD cases, we identified an NKX2-5 mutation. In addition to the heterogeneity of NKX2-5 mutations, a diversity of phenotypes occurred within the families with predominant ASD and AV block. We did in fact identify a large prevalence of Sudden Cardiac Death (SCD) in families with truncating mutations, and two patients with coronary sinus disease. NKX2-5 is thus responsible for dominant familial ASD even in consanguineous populations, and a wide genetic and phenotypic diversity is characteristic of NKX2-5 mutations in the Lebanese population.
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Huang CH, Chiu PC, Liu HC, Lu YH, Huang JK, Charng MJ, Niu DM. Clinical observations and treatment of pediatric homozygous familial hypercholesterolemia due to a low-density lipoprotein receptor defect. J Clin Lipidol 2015; 9:234-40. [DOI: 10.1016/j.jacl.2014.11.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 11/12/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
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Sirtori CR, Pavanello C, Bertolini S. Microsomal transfer protein (MTP) inhibition-a novel approach to the treatment of homozygous hypercholesterolemia. Ann Med 2014; 46:464-74. [PMID: 24987866 DOI: 10.3109/07853890.2014.931100] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Homozygous familial hypercholesterolemia (HoFH) represents the most severe lipoprotein disorder, generally attributable to mutation(s) of the low-density lipoprotein receptor (LDL-R), i.e. autosomal dominant hypercholesterolemia type 1 (ADH1). Much lower percentages are due to alterations of apolipoprotein B (ADH2), or gain-of-function mutations of proprotein convertase subtilisin/kexin type 9 (PCSK9) (ADH3). In certain geographical areas a significant number of patients may be affected by an autosomal recessive hypercholesterolemia (ARH). Mutations may be also combined (two mutations of the same gene, compound heterozygosity), or two in different genes (double heterozygosity). Among the most innovative therapeutic approaches made available recently, inhibitors of the microsomal transfer protein (MTP) system have shown a high clinical potential. MTP plays a critical role in the assembly/secretion of very-low-density lipoproteins (VLDL), and its absence leads to apo B deficiency. MTP antagonists dramatically lower LDL-cholesterol (LDL-C) in animals, although a reported increase of liver fat delayed their clinical development. Lomitapide, the best-studied MTP inhibitor, reduces LDL-C by 50% or more in HoFH patients, with modest, reversible, liver steatosis. Recent US approval has confirmed an acceptable tolerability, provided patients adhere to a strictly low-fat regimen. There are no clinical data on atherosclerosis reduction/regression, but animal models provide encouraging results.
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Klose G, Laufs U, März W, Windler E. Familial hypercholesterolemia: developments in diagnosis and treatment. DEUTSCHES ARZTEBLATT INTERNATIONAL 2014; 111:523-9. [PMID: 25145510 PMCID: PMC4148715 DOI: 10.3238/arztebl.2014.0523] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 08/25/2013] [Accepted: 03/21/2014] [Indexed: 01/03/2023]
Abstract
BACKGROUND Familial hypercholesterolemia (FH) is a congenital disorder of lipid metabolism characterized by a marked elevation of the plasma concentration of LDL (low-density lipoprotein) cholesterol beginning in childhood and by the early onset of coronary heart disease. It is among the commonest genetic disorders, with an estimated prevalence in Germany of at least 1 per 500 persons. METHOD Review of pertinent literature retrieved by a selective search. RESULTS FH is underdiagnosed and undertreated in Germany. It is clinically diagnosed on the basis of an elevated LDL cholesterol concentration (>190 mg/dL [4.9 mmol/L]), a family history of hypercholesterolemia, and early coronary heart disease, or the demonstration of xanthomas. The gold standard of diagnosis is the identification of the underlying genetic defect, which is possible in 80% of cases and enables the identification of affected relatives of the index patient. The recommended goals of treatment, based on the results of observational studies, are to lower the LDL cholesterol concentration by at least 50% or to less than 100 mg/dL (2.6 mmol/L) (for children: <135 mg/dL [3.5 mmol/L]). The target value is lower for patients with clinically overt atherosclerosis (<70 mg/dL [1.8 mmol/L]). Statins, combined with a health-promoting lifestyle, are the treatment of choice. Lipoprotein apheresis is used in very severe cases; its therapeutic effects on clinical endpoints and its side effect profile have not yet been documented in randomized controlled trials. CONCLUSION Familial hypercholesterolemia is a common disease that can be diagnosed simply and reliably on clinical grounds and by molecular genetic testing. Timely diagnosis and appropriate treatment can lower the risk of atherosclerosis in heterozygous patients to that of the general population.
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Affiliation(s)
- Gerald Klose
- Private practice for Internal Medicine, Gastroenterology, Cardiology and Preventional Medicine: Dres. T. Beckenbauer und S. Maierhof and joint practice Dres. K. W. Spieker and I van de Loo, Bremen
| | - Ulrich Laufs
- Department of Internal Medicine III—Cardiology, Angiology and Intensive Care Medicine, Saarland University Medical Center, Homburg/Saar
| | - Winfried März
- Medical Clinic V (Nephrology, Hypertensiology, Endocrinology, Diabetology, Rheumatology), Department of Internal Medicine, Mannheim Medical Faculty, University of Heidelberg, Mannheim
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University Graz
- Synlab Academy, Synlab Services GmbH, Mannheim
| | - Eberhard Windler
- Preventive Medicine, Department of General and Interventional Cardiology, University Hospital Hamburg-Eppendorf, Hamburg
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Page MM, Bell DA, Hooper AJ, Watts GF, Burnett JR. Lipoprotein apheresis and new therapies for severe familial hypercholesterolemia in adults and children. Best Pract Res Clin Endocrinol Metab 2014; 28:387-403. [PMID: 24840266 DOI: 10.1016/j.beem.2013.10.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Familial hypercholesterolemia (FH), the most common and severe monogenic form of hypercholesterolemia, is an autosomal co-dominant disease characterized by an increased plasma low density lipoprotein (LDL)-cholesterol concentration and premature coronary heart disease (CHD). The clinical phenotype depends on the gene involved and severity of mutation (or mutations) present. Patients with homozygous or compound heterozygous FH have severe hypercholesterolemia (LDL-cholesterol >13 mmol/L) due to a gene dosing effect and without treatment have accelerated atherosclerotic CHD from birth, and frequently die of CHD before age 30. Cholesterol-lowering therapies have been shown to reduce both mortality and major adverse cardiovascular events in individuals with FH. Lipoprotein apheresis concomitant with lipid-lowering therapy is the treatment of choice for homozygous FH. This article describes the rationale and role of lipoprotein apheresis in the treatment of severe FH and outlines the recent advances in new pharmacotherapies for this condition.
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Affiliation(s)
- Michael M Page
- Lipid Disorders Clinic, Department of Internal Medicine, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Damon A Bell
- Lipid Disorders Clinic, Department of Internal Medicine, Royal Perth Hospital, Perth, Western Australia, Australia; Department of Clinical Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Western Australia, Australia; School of Medicine & Pharmacology, University of Western Australia, Perth, Western Australia, Australia
| | - Amanda J Hooper
- Department of Clinical Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Western Australia, Australia; School of Medicine & Pharmacology, University of Western Australia, Perth, Western Australia, Australia; School of Pathology & Laboratory Medicine, University of Western Australia, Perth, Western Australia, Australia
| | - Gerald F Watts
- Lipid Disorders Clinic, Department of Internal Medicine, Royal Perth Hospital, Perth, Western Australia, Australia; School of Medicine & Pharmacology, University of Western Australia, Perth, Western Australia, Australia
| | - John R Burnett
- Lipid Disorders Clinic, Department of Internal Medicine, Royal Perth Hospital, Perth, Western Australia, Australia; Department of Clinical Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Western Australia, Australia; School of Medicine & Pharmacology, University of Western Australia, Perth, Western Australia, Australia.
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Vuorio A, Tikkanen MJ, Kovanen PT. Inhibition of hepatic microsomal triglyceride transfer protein - a novel therapeutic option for treatment of homozygous familial hypercholesterolemia. Vasc Health Risk Manag 2014; 10:263-70. [PMID: 24851052 PMCID: PMC4018418 DOI: 10.2147/vhrm.s36641] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Familial hypercholesterolemia (FH) is an autosomal dominant disease caused by mutations in the low-density lipoprotein (LDL)-receptor gene (LDLR). Patients with homozygous FH (hoFH) have inherited a mutated LDLR gene from both parents, and therefore all their LDL-receptors are incapable of functioning normally. In hoFH, serum LDL levels often exceed 13 mmol/L and tendon and cutaneous xanthomata appear early (under 10 years of age). If untreated, this extremely severe form of hypercholesterolemia may cause death in childhood or in early adulthood. Based on recent data, it can be estimated that the prevalence of hoFH is about 1:500,000 or even 1:400,000. Until now, the treatment of hoFH has been based on high-dose statin treatment combined with LDL apheresis. Since the LDL cholesterol-lowering effect of statins is weak in this disease, and apheresis is a cumbersome treatment and not available at all centers, alternative novel pharmaceutical therapies are needed. Lomitapide is a newly introduced drug, capable of effectively decreasing serum LDL cholesterol concentration in hoFH. It inhibits the microsomal triglyceride transfer protein (MTTP). By inhibiting in hepatocytes the transfer of triglycerides into very low density lipoprotein particles, the drug blocks their assembly and secretion into the circulating blood. Since the very low density lipoprotein particles are precursors of LDL particles in the circulation, the reduced secretion of the former results in lower plasma concentration of the latter. The greatest concern in lomitapide treatment has been the increase in liver fat, which can be, however, counteracted by strictly adhering to a low-fat diet. Lomitapide is a welcome addition to the meager selection of drugs currently available for the treatment of refractory hypercholesterolemia in hoFH patients.
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Affiliation(s)
- Alpo Vuorio
- Health Center Mehiläinen, Vantaa, Finland ; Finnish Institute of Occupational Health, Lappeenranta, Finland
| | - Matti J Tikkanen
- Heart and Lung Center, Helsinki University Central Hospital, Folkhälsan Research Center, Biomedicum, Helsinki, Finland
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Sjouke B, Kusters DM, Kindt I, Besseling J, Defesche JC, Sijbrands EJ, Roeters van Lennep JE, Stalenhoef AF, Wiegman A, de Graaf J, Fouchier SW, Kastelein JJ, Hovingh GK. Homozygous autosomal dominant hypercholesterolaemia in the Netherlands: prevalence, genotype–phenotype relationship, and clinical outcome. Eur Heart J 2014; 36:560-5. [DOI: 10.1093/eurheartj/ehu058] [Citation(s) in RCA: 310] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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Panno MD, Cefalù AB, Averna MR. Lomitapide: a novel drug for homozygous familial hypercholesterolemia. ACTA ACUST UNITED AC 2014. [DOI: 10.2217/clp.13.74] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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31
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Fahed AC, Habib RH, Nemer GM, Azar ST, Andary RR, Arabi MT, Moubarak EM, Bitar FF, Haddad FF. Low-Density Lipoprotein Levels and Not Mutation Status Predict Intima-Media Thickness in Familial Hypercholesterolemia. Ann Vasc Surg 2014; 28:421-6. [DOI: 10.1016/j.avsg.2013.02.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 01/30/2013] [Accepted: 02/16/2013] [Indexed: 11/15/2022]
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Abstract
Lomitapide (Juxtapid(TM)), an orally administered inhibitor of the microsomal triglyceride transfer protein, inhibits the synthesis of chylomicrons and very low-density lipoprotein, thereby reducing plasma levels of low-density lipoprotein cholesterol (LDL-C). Lomitapide is used to lower lipid levels in adults with homozygous familial hypercholesterolemia, a rare, potentially life-threatening genetic disease that is commonly caused by mutations in the LDL receptor gene or other genes that affect the function of the LDL receptor. In a multinational single-arm, open-label, 78-week, phase III trial, lomitapide reduced mean plasma LDL-C levels by 50 % from baseline in 23 evaluable adults with homozygous familial hypercholesterolemia over a 26 week treatment period. Reductions from baseline in LDL-C levels were sustained for up to 78 weeks with continued lomitapide treatment. In this study, the initial dosage of lomitapide was 5 mg once daily for two weeks, with upward titration thereafter to 10, 20, 40, and 60 mg at weeks 2, 6, 10, and 14, respectively, or until an individually assessed maximum dosage was achieved. Prior to the start of treatment with lomitapide, other lipid-lowering therapy (including LDL apheresis) was stabilized over a 6-week period, and then continued throughout the lomitapide treatment phase. Lomitapide was generally well tolerated; the most common adverse events in the phase III trial were gastrointestinal events.
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Affiliation(s)
- Caroline M Perry
- Adis, 41 Centorian Drive, Private Bag 65901 Mairangi Bay, North Shore, 0754, Auckland, New Zealand.
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Walzer S, Travers K, Rieder S, Erazo-Fischer E, Matusiewicz D. Homozygous familial hypercholesterolemia (HoFH) in Germany: an epidemiological survey. CLINICOECONOMICS AND OUTCOMES RESEARCH 2013; 5:189-92. [PMID: 23662069 PMCID: PMC3647446 DOI: 10.2147/ceor.s43087] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Introduction In Europe a disease is recognized as rare if less than 1 in 2000 people suffer from the specific disease. In patients with familial homozygous hypercholesterolemia (HoFH) the accumulation of low-density lipoprotein cholesterol (LDL-C) leads to generalized atherosclerosis due to an insufficient functioning of the LDL-C receptors. Patients die early sometimes even in the mid-30s, from myocardial infarction or stroke. For the German population, insufficient epidemiological evidence exists. Methods A systematic literature search in EMBASE and Medline was performed in conjunction with a targeted manual search for epidemiological HoFH studies. Additionally a nationwide survey was conducted in Germany in all identified apheresis- and lipid centers. The purpose of the survey was the validation of the systematic literature search results based on empirical (practice) data. Results In total 961 publications were found, 874 were excluded based on pre-defined exclusion criteria leaving only 87 for further review. After review of the identified abstracts (n = 87) 23 publications were identified as epidemiological studies. Only one publication was found which reported a prevalence of 1:1,000,000. The qualitative survey among 187 physicians in Germany also revealed a low prevalence: 95 HoFH patients were identified in 35 centers. Conclusion The estimated frequency of homozygous familial hypercholesterolemia patients in Germany is around 95 (1:860,000) and the disease should be recognized as rare according to the definition of the European Medical Agency.
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Affiliation(s)
- S Walzer
- MArS Market Access and Pricing Strategy UG (hb), Weil am Rhein, Germany
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Soufi M, Rust S, Walter M, Schaefer JR. A combined LDL receptor/LDL receptor adaptor protein 1 mutation as the cause for severe familial hypercholesterolemia. Gene 2013; 521:200-3. [DOI: 10.1016/j.gene.2013.03.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 12/23/2012] [Accepted: 03/07/2013] [Indexed: 01/24/2023]
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Bell DA, Hooper AJ, Watts GF, Burnett JR. Mipomersen and other therapies for the treatment of severe familial hypercholesterolemia. Vasc Health Risk Manag 2012; 8:651-9. [PMID: 23226021 PMCID: PMC3513909 DOI: 10.2147/vhrm.s28581] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Familial hypercholesterolemia (FH) is an autosomal dominant condition with a population prevalence of one in 300–500 (heterozygous) that is characterized by high levels of low-density lipoprotein (LDL) cholesterol, tendon xanthomata, and premature atherosclerosis and coronary heart disease (CHD). FH is caused mainly by mutations in the LDLR gene. However, mutations in other genes including APOB and PCSK9, can give rise to a similar phenotype. Homozygous FH with an estimated prevalence of one in a million is associated with severe hypercholesterolemia with accelerated atherosclerotic CHD in childhood and without treatment, death usually occurs before the age of 30 years. Current approaches for the treatment of homozygous FH include statin-based lipid-lowering therapies and LDL apheresis. Mipomersen is a second-generation antisense oligonucleotide (ASO) targeted to human apolipoprotein B (apoB)-100. This review provides an overview of the pathophysiology and current treatment options for familial hypercholesterolemia and describes novel therapeutic strategies focusing on mipomersen, an antisense apoB synthesis inhibitor. Mipomersen is distributed mainly to the liver where it silences apoB mRNA, thereby reducing hepatic apoB-100 and giving rise to reductions in plasma total cholesterol, LDL-cholesterol, and apoB concentrations in a dose-and time-dependent manner. Mipomersen has been shown to decrease apoB, LDL-cholesterol and lipoprotein(a) in patients with heterozygous and homozygous FH on maximally tolerated lipid-lowering therapy. The short-term efficacy and safety of mipomersen has been established, however, injection site reactions are common and concern exists regarding the long-term potential for hepatic steatosis with this ASO. In summary, mipomersen given alone or in combination with standard lipid-lowering medications shows promise as an adjunct therapy in patients with homozygous or refractory heterozygous FH at high risk of atherosclerotic CHD, who are not at target or are intolerant of statins.
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Affiliation(s)
- Damon A Bell
- Department of Core Clinical Pathology and Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Western Australia, Australia
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Fahed AC, Nassar AH. Pregnancy in a woman with homozygous familial hypercholesterolemia not on low-density lipoprotein apheresis. AJP Rep 2012; 2:33-6. [PMID: 23946902 PMCID: PMC3653520 DOI: 10.1055/s-0032-1305798] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 12/03/2011] [Indexed: 10/28/2022] Open
Abstract
Pregnancy in women with homozygous familial hypercholesterolemia (FH) has been rarely reported and might pose risks on the mother and her fetus. Although most reported cases remained on low-density lipoprotein (LDL) apheresis, there are no clear guidelines regarding the management of this entity. We report the first case of an uncomplicated pregnancy in a 24-year-old homozygous FH woman who was not maintained on LDL apheresis. FH expresses a wide variability in the phenotype, and management of homozygous FH cases who desire to become pregnant should be individualized based on preconceptional assessment with frequent antenatal follow-up. Decisions on management should be made after weighing the risks versus benefits of LDL apheresis.
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Affiliation(s)
- Akl C Fahed
- Department of Genetics, Harvard Medical School, Boston, Massachusetts
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Fahed AC, Bitar FF, Khalaf RI, Moubarak EM, Azar ST, Nemer GM. The Lebanese allele at the LDLR in normocholesterolemic people merits reconsideration of genotype phenotype correlations in familial hypercholesterolemia. Endocrine 2012; 42:445-8. [PMID: 22487947 DOI: 10.1007/s12020-012-9669-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 03/31/2012] [Indexed: 11/26/2022]
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Raal FJ, Santos RD. Homozygous familial hypercholesterolemia: Current perspectives on diagnosis and treatment. Atherosclerosis 2012; 223:262-8. [DOI: 10.1016/j.atherosclerosis.2012.02.019] [Citation(s) in RCA: 250] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2011] [Revised: 02/07/2012] [Accepted: 02/08/2012] [Indexed: 11/24/2022]
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Shawar SM, Al-Drees MA, Ramadan AR, Ali NH, Alfadhli SM. The Arabic allele: a single base pair substitution activates a 10-base downstream cryptic splice acceptor site in exon 12 of LDLR and severely decreases LDLR expression in two unrelated Arab families with familial hypercholesterolemia. Atherosclerosis 2011; 220:429-36. [PMID: 22129472 DOI: 10.1016/j.atherosclerosis.2011.10.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 10/14/2011] [Accepted: 10/30/2011] [Indexed: 10/15/2022]
Abstract
Familial hypercholesterolemia (FH) is a monogenic autosomal dominant disorder caused by defects in LDLR. Few reports describe FH mutations among Arabs. We describe a mutation in LDLR of two unrelated Arab families. We investigated 19 patients using DNA sequencing, RFLP, and real-time (RT) PCR. DNA sequencing showed a base pair substitution (c.1706-2 A>T) in the splice acceptor site of LDLR intron 11. Our results were confirmed by RFLP on 2% agarose gel. In silico analysis predicted a new cryptic splice site downstream of the original position generating a 10-base deletion from the beginning of exon 12; (c.1706-1715del.ATCTCCTCAG). cDNA sequencing of exon 12 confirmed the computational analysis. The deletion was visualized on 4% agarose gel. The deletion generates a frameshift and a premature termination codon (c.1991-1993; p.(Asp569Valfs*93). RT-PCR revealed that LDLR mRNA is 9.3%±6.5 and 17.9%±8.0 for FH homozygote and heterozygote individuals respectively, compared to a healthy family control. We predict a class II LDLR mutation that leads to a truncated receptor missing exons 14-18. We called this mutation "the Arabic allele". We expect a significant contribution of this mutation to the prevalence of FH among Arabs. Also, we propose that the severe down regulation of LDLR mRNA expression is due to nonsense-mediated-decay.
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Affiliation(s)
- Said M Shawar
- Biotechnology Program, Arabian Gulf University, Manama, Bahrain.
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Moutran R, Maatouk I, Tomb R. Xanthomes cutanés géants révélant une hypercholestérolémie familiale homozygote. Ann Dermatol Venereol 2011; 138:798-9. [DOI: 10.1016/j.annder.2011.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Revised: 06/03/2011] [Accepted: 06/24/2011] [Indexed: 11/15/2022]
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Familial hypercholesterolemia: the lipids or the genes? Nutr Metab (Lond) 2011; 8:23. [PMID: 21513517 PMCID: PMC3104361 DOI: 10.1186/1743-7075-8-23] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 04/22/2011] [Indexed: 02/05/2023] Open
Abstract
Familial Hypercholesterolemia (FH) is a common cause of premature cardiovascular disease and is often undiagnosed in young people. Although the disease is diagnosed clinically by high LDL cholesterol levels and family history, to date there are no single internationally accepted criteria for the diagnosis of FH. Several genes have been shown to be involved in FH; yet determining the implications of the different mutations on the phenotype remains a hard task. The polygenetic nature of FH is being enhanced by the discovery of new genes that serve as modifiers. Nevertheless, the picture is still unclear and many unknown genes contributing to the phenotype are most likely involved. Because of this evolving polygenetic nature, the diagnosis of FH by genetic testing is hampered by its cost and effectiveness. In this review, we reconsider the clinical versus genetic nomenclature of FH in the literature. After we describe each of the genetic causes of FH, we summarize the known correlation with phenotypic measures so far for each genetic defect. We then discuss studies from different populations on the genetic and clinical diagnoses of FH to draw helpful conclusions on cost-effectiveness and suggestions for diagnosis.
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