A rare gain of function variant of hepatic lipase attenuates hypercholesterolaemia and atherosclerosis in mice via an LDL receptor-independent mechanism.

Aims: LIPC encodes hepatic lipase (HL), a liver-bound protein with both phospholipase and triglyceride lipase activity, and involved in the catabolism of circulating lipoproteins. We recently identified the gain-of-function variant HL-E97G, with selectively increased phospholipase activity, as a new genetic cause of familial combined hypocholesterolaemia in humans. The role of HL in the development of atherosclerosis remains controversial.

KILDA: identifying KIV-2 repeats from kmers.

High concentration of lipoprotein(a) [Lp(a)], a lipoprotein with proatherogenic properties, is an important risk factor for cardiovascular disease. This concentration is mostly genetically determined by a complex interplay between the number of kringle IV type 2 repeats and Lp(a)-affecting variants. Besides Lp(a) plasma concentration, there is an unmet need to identify individuals most at risk based on their genotype.

Minigene splicing reporter assay: a high-stake tool for genetic diagnosis in familial hypobetalipoproteinemia.

Background & Aims: Familial hypobetalipoproteinemia 1 (FHBL-SD2) is the most common monogenic form of primary hypocholesterolaemia, related to truncating variants in the APOB gene encoding apolipoprotein B. Due to its high level of complexity, variants of uncertain significance (VUS) require further investigations. This study aims to demonstrate the value of setting minigene assays in the FHBL-SD2's genetic diagnosis.

Mobile Element Insertion in the APOB Exon 3 Coding Sequence: A New Challenge in Hypobetalipoproteinemia Diagnosis.

Mobile elements (ME) can transpose by copy-and-paste mechanisms. A heterozygous insertion in APOB exon 3 coding sequence was suspected in a patient with hypobetalipoproteinemia (HBL), by gel electrophoresis of the PCR products. An insertion of a 85 bp fragment flanked by a polyA stretch and a target replication site duplication was identified as a ME insertion (MEI) from the AluYa5 subfamily, NM_000384.

Assessment of three equations to calculate plasma LDL cholesterol concentration in fasting and non-fasting hypertriglyceridemic patients.

Objectives: Low-density lipoprotein cholesterol (LDL-C) concentration was calculated for many years using the Friedewald equation, but those from Sampson and extended-Martin-Hopkins perform differently. Their accuracy in fasting hypertriglyceridemia and non-fasting state were compared and the clinical impact of implementing these equations on risk classification and on the setting of lipid treatment goals was assessed.

Methods: Seven thousand six standard lipid profiles and LDL-C concentrations measured after ultracentrifugation (uLDL-C) were retrospectively included.

Additive Effect of Rare Variants on the Phenotype of Familial Hypercholesterolemia.

Background: Autosomal dominant hypercholesterolemia (ADH) is due to deleterious variants in , , or genes. Double heterozygote for these genes induces a more severe phenotype. More recently, a new causative variant of heterozygous ADH was identified in .

New CRISPR Technology for Creating Cell Models of Lipoprotein Assembly and Secretion.

Purpose Of Review: This review is aimed at providing an overview of new developments in gene editing technology, including examples of how this technology has been used to develop cell models for studying the effects of gene ablation or missense mutations on lipoprotein assembly and secretion.

Recent Findings: CRISPR/Cas9-mediated gene editing is superior to other technologies because of its ease, sensitivity, and low off-target effects. This technology has been used to study the importance of microsomal triglyceride transfer protein in the assembly and secretion of apolipoprotein B-containing lipoproteins, as well as to establish causal effects of APOB gene missense mutations on lipoprotein assembly and secretion.

A new 165-SNP low-density lipoprotein cholesterol polygenic risk score based on next generation sequencing outperforms previously published scores in routine diagnostics of familial hypercholesterolemia.

Genetic diagnosis of familial hypercholesterolemia (FH) remains unexplained in 30 to 70% of patients after exclusion of monogenic disease. There is now a growing evidence that a polygenic burden significantly modulates LDL-cholesterol (LDL-c) concentrations. Several LDL-c polygenic risk scores (PRS) have been set up.

Guidance for the diagnosis and treatment of hypolipidemia disorders.

The Abetalipoproteinemia and Related Disorders Foundation was established in 2019 to provide guidance and support for the life-long management of inherited hypocholesterolemia disorders. Our mission is "to improve the lives of individuals and families affected by abetalipoproteinemia and related disorders". This review explains the molecular mechanisms behind the monogenic hypobetalipoproteinemia disorders and details their specific pathophysiology, clinical presentation and management throughout the lifespan.

Factors Predicting Statin Initiation During Childhood in Familial Hypercholesterolemia: Importance of Genetic Diagnosis.

Objective: To identify childhood and parental factors associated with initiation of statin therapy in children with heterozygous familial hypercholesterolemia (HeFH), including underlying genetic diagnosis or parental premature atherosclerotic cardiovascular disease (ASCVD).

Study Design: This multicenter cohort study included 245 HeFH child-parent pairs from the REFERCHOL national register (2014-2020). Demographic and clinical characteristics at the last visit were collected.

Variants in the Gene Are Associated With a Favorable Cardiometabolic Risk Profile.

Background: In mice, GPR146 (G-protein-coupled receptor 146) deficiency reduces plasma lipids and protects against atherosclerosis. Whether these findings translate to humans is unknown.

Methods: Common and rare genetic variants in the gene locus were used as research instruments in the UK Biobank.

Identification of a Gain-of-Function Variant as a Novel Cause of Familial Combined Hypocholesterolemia.

Background: Atherosclerotic cardiovascular disease is the main cause of mortality worldwide and is strongly influenced by circulating low-density lipoprotein (LDL) cholesterol levels. Only a few genes causally related to plasma LDL cholesterol levels have been identified so far, and only 1 gene, , has been causally related to combined hypocholesterolemia. Here, our aim was to elucidate the genetic origin of an unexplained combined hypocholesterolemia inherited in 4 generations of a French family.

A meal rich in palm oil or butter modifies the sphingolipid profile of postprandial triglyceride-rich lipoproteins from type 2 diabetic women.

Elevated concentrations of triglyceride-rich lipoproteins (TGRL) in the fasting and postprandial states are risk factors for cardiovascular events, especially in type 2 diabetes (T2D). T2D modifies the lipid composition of plasma and lipoproteins and some sphingolipids (SP) have been validated as potent predictive biomarkers of cardiovascular disease occurrence. The main objectives of the present study were to characterize the plasma SP profile in fasting T2D patients and to determine whether SP are modified in postprandial TGRL from these patients compared to fasting TGRL.

Molecular Spectrum in a French Cohort with Primary Dyslipidemia.

Primary hypercholesterolemia is characterized by elevated LDL-cholesterol (LDL-C) levels isolated in autosomal dominant hypercholesterolemia (ADH) or associated with elevated triglyceride levels in familial combined hyperlipidemia (FCHL). Rare variants are known in ADH and FCHL. We explored the molecular spectrum in a French ADH/FCHL cohort of 5743 unrelated probands.

CRISPR-Cas9 Engineering in Hypobetalipoproteinemia: A Promising Tool for Functional Studies of Novel Variants.

Hypobetalipoproteinemia is characterized by LDL-cholesterol and apolipoprotein B (apoB) plasma levels below the fifth percentile for age and sex. Familial hypobetalipoproteinemia (FHBL) is mostly caused by premature termination codons in the gene, a condition associated with fatty liver and steatohepatitis. Nevertheless, many families with a FHBL phenotype carry missense variants of uncertain significance (VUS).