Molecular genetics in 1991 arrhythmia probands and 2782 relatives in Norway: Results from 17 years of genetic testing in a national laboratory.

The aim of this study was to explore the prevalence of likely pathogenic or pathogenic variants and assess the diagnostic yield from genetic testing for cardiac arrhythmias in Norway since 2003. Data from 1991 probands and 2782 relatives were retrospectively collected from the laboratory information management system at Unit for Cardiac and Cardiovascular Genetics, Oslo University hospital. Of 1991 probands, 57.

Flavonoids regulate LDLR through different mechanisms tied to their specific structures.

Flavonoids, polyphenolic compounds found in plant-based diets, are associated with reduced risk of cardiovascular disease and longevity. These components are reported to reduce plasma levels of low-density lipoprotein (LDL) through an upregulation of the LDL receptor (LDLR), but the mechanism is still largely unknown. In this study, we have systematically screened the effect of 12 flavonoids from six different flavonoid subclasses on the effect on LDLR.

Functional characterization of missense variants affecting the extracellular domains of ABCA1 using a fluorescence-based assay.

Excess cholesterol originating from nonhepatic tissues is transported within HDL particles to the liver for metabolism and excretion. Cholesterol efflux is initiated by lipid-free or lipid-poor apolipoprotein A1 interacting with the transmembrane protein ABCA1, a key player in cholesterol homeostasis. Defective ABCA1 results in reduced serum levels of HDL cholesterol, deposition of cholesterol in arteries, and an increased risk of early onset CVD.

Molecular genetic testing and measurement of levels of GPIHBP1 autoantibodies in patients with severe hypertriglyceridemia: The importance of identifying the underlying cause of hypertriglyceridemia.

Background: Severe hypertriglyceridemia can be caused by pathogenic variants in genes encoding proteins involved in the metabolism of triglyceride-rich lipoproteins. A key protein in this respect is lipoprotein lipase (LPL) which hydrolyzes triglycerides in these lipoproteins. Another important protein is glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPIHBP1) which transports LPL to the luminal side of the endothelial cells.

Missense mutation Q384K in the APOB gene affecting the large lipid transfer module of apoB reduces the secretion of apoB-100 in the liver without reducing the secretion of apoB-48 in the intestine.

Background: Molecular genetic testing of patients with hypobetalipoproteinemia may identify a genetic cause that can form the basis for starting proper therapy. Identifying a genetic cause may also provide novel data on the structure-function relationship of the mutant protein.

Objective: To identify a genetic cause of hypobetalipoproteinemia in a patient with levels of low density lipoprotein cholesterol at the detection limit of 0.

Risk of stroke in genetically verified familial hypercholesterolemia: A prospective matched cohort study.

Background And Aims: Individuals with familial hypercholesterolemia (FH), causing severely elevated LDL-C, are expected to have a higher risk of ischemic stroke. The risk of hemorrhagic stroke and impact of statin use are, however, not known. We aimed to investigate the risk of incident total, ischemic and hemorrhagic stroke in individuals with FH compared to controls, and to explore the association between cumulative statin use and risk of total stroke in FH.

Cascade screening for familial hypercholesterolemia should be organized at a national level.

Purpose Of Review: Patients with familial hypercholesterolemia (FH) have a markedly increased risk of premature cardiovascular disease. However, there are effective lipid-lowering therapies available to reduce the risk of cardiovascular disease. This makes it important to diagnose these patients.

Molecular genetics in 4408 cardiomyopathy probands and 3008 relatives in Norway: 17 years of genetic testing in a national laboratory.

Aims: To describe results from genetic testing for cardiomyopathies in a national laboratory for genetic testing in Norway since 2003.

Methods And Results: Retrospective data collection from the laboratory information management system at Unit for Cardiac and Cardiovascular Genetics, Oslo University hospital. Data from 4408 probands and 3008 relatives were available.

Association of Familial Hypercholesterolemia and Statin Use With Risk of Dementia in Norway.

Importance: Hypercholesterolemia, which is a cardiovascular risk factor, may also be associated with dementia risk. The benefit of statin treatment on dementia risk is controversial.

Objective: To determine whether individuals with familial hypercholesterolemia (FH), who have been exposed to lifelong hypercholesterolemia, have an excess risk of dementia and whether statin use is associated with dementia risk.

The importance of cascade genetic screening for diagnosing autosomal dominant hypercholesterolemia: Results from twenty years of a national screening program in Norway.

Background: The most cost-effective strategy to diagnose patients with autosomal dominant hypercholesterolemia (ADH) is to perform cascade genetic screening.

Objective: To present the cascade genetic screening program for ADH in Norway.

Methods: A national cascade genetic screening program for ADH in Norway has been operating at Unit for Cardiac and Cardiovascular Genetics, Oslo University Hospital for twenty years.

Molecular genetic testing for autosomal dominant hypercholesterolemia in 29,449 Norwegian index patients and 14,230 relatives during the years 1993-2020.

Background And Aims: In this study, we present the status regarding molecular genetic testing for mutations in the genes encoding the low density lipoprotein receptor (LDLR), apolipoprotein B (APOB) and proprotein convertase subtilisin/kexin type 9 (PCSK9) as causes of autosomal dominant hypercholesterolemia (ADH) in Norway.

Methods: We have extracted data from the laboratory information management system at Unit for Cardiac and Cardiovascular Genetics, Oslo University Hospital for the period 1993-2020. This laboratory is the sole laboratory performing molecular genetic testing for ADH in Norway.

2.5-fold increased risk of recurrent acute myocardial infarction with familial hypercholesterolemia.

Background And Aims: A first-time acute myocardial infarction (AMI) is a severe diagnosis that leads to initiation or intensification of lipid-lowering medication to prevent recurrent events. Individuals with familial hypercholesterolemia (FH) already use high-intensity lipid-lowering medication at the time of an incident AMI due to their diagnosis. Hence, we hypothesized that compared with matched non-FH controls, individuals with genetically verified FH have increased mortality and risk of recurrent AMI after their first event.

Prevalence of genetically verified familial hypercholesterolemia among young (<45 years) Norwegian patients hospitalized with acute myocardial infarction.

Background: Patients with familial hypercholesterolemia (FH) have an increased risk of premature myocardial infarction (MI).

Objectives: The objective of the study is to investigate the prevalence of FH among young patients hospitalized with acute MI.

Methods: Data were collected from medical charts of all patients aged <45 years admitted with acute MI to the Department of Cardiology, Oslo University Hospital Ullevål, in the period 2012 to 2016.

Lower risk of smoking-related cancer in individuals with familial hypercholesterolemia compared with controls: a prospective matched cohort study.

According to guidelines, individuals with familial hypercholesterolemia (FH) shall receive lifestyle intervention and intensive lipid-lowering treatment from early in life to reduce the risk of coronary heart disease. Our aim was to study if treatment of FH also could affect risk of lifestyle-related cancer. We presented cumulative incidence of total cancer and lifestyle-related cancer sites in individuals with genetically verified FH (n = 5531) compared with age and sex matched controls (n = 108354).

Association of Low-Density Lipoprotein Cholesterol With Risk of Aortic Valve Stenosis in Familial Hypercholesterolemia.

Importance: Aortic valve stenosis (AS) is the most common valve disease. Elevated levels of low-density lipoprotein (LDL) cholesterol are a risk factor; however, lipid-lowering treatment seems not to prevent progression of AS. The importance of LDL cholesterol in the development of AS thus remains unclear.

Bone morphogenetic protein 1 cleaves the linker region between ligand-binding repeats 4 and 5 of the LDL receptor and makes the LDL receptor non-functional.

The cell-surface low-density lipoprotein receptor (LDLR) internalizes low-density lipoprotein (LDL) by receptor-mediated endocytosis and plays a key role in the regulation of plasma cholesterol levels. The ligand-binding domain of the LDLR contains seven ligand-binding repeats of approximately 40 residues each. Between ligand-binding repeats 4 and 5, there is a 10-residue linker region that is subject to enzymatic cleavage.

Lysosomal acid lipase does not have a propeptide and should not be considered being a proprotein.

Lysosomal acid lipase (LAL) plays an important role in lipid metabolism by performing hydrolysis of triglycerides and cholesteryl esters in the lysosome. Based upon characteristics of LAL purified from human liver, it has been proposed that LAL is a proprotein with a 55 residue propeptide that may be essential for proper folding, intracellular transport, or enzymatic function. However, the biological significance of such a propeptide has not been fully elucidated.

Strategies to prevent cleavage of the linker region between ligand-binding repeats 4 and 5 of the LDL receptor.

A main strategy for lowering plasma low-density lipoprotein (LDL) cholesterol levels is to increase the number of cell-surface LDL receptors (LDLRs). This can be achieved by increasing the synthesis or preventing the degradation of the LDLR. One mechanism by which an LDLR becomes non-functional is enzymatic cleavage within the 10 residue linker region between ligand-binding repeats 4 and 5.

Characterization of the mechanisms by which missense mutations in the lysosomal acid lipase gene disrupt enzymatic activity.

Hydrolysis of cholesteryl esters and triglycerides in the lysosome is performed by lysosomal acid lipase (LAL). In this study we have investigated how 23 previously identified missense mutations in the LAL gene (LIPA) (OMIM# 613497) affect the structure of the protein and thereby disrupt LAL activity. Moreover, we have performed transfection studies to study intracellular transport of the 23 mutants.

Risk of Ischemic Stroke and Total Cerebrovascular Disease in Familial Hypercholesterolemia: A Register Study From Norway.

Background and Purpose- Familial hypercholesterolemia (FH) is a common autosomal dominant disease leading to increased level of serum LDL (low-density lipoprotein) cholesterol and risk of coronary heart disease. Whether FH increases the risk of cerebrovascular disease, including ischemic stroke, is debated. Accordingly, we studied the incidence of cerebrovascular disease in a cohort of people with genetically verified FH compared with the entire Norwegian population and examined whether people in this cohort with previous cohort had increased risk of cerebrovascular disease.