biostudies-literatureUnknown62Targonska M<h4>Background and aims</h4>Familial hypercholesterolemia is a genetic disorder caused by pathogenic or likely pathogenic variants in four key genes: <i>LDLR</i>, <i>APOB</i>, <i>PCSK9,</i> and <i>APOE</i>. It leads to elevated levels of low-density lipoprotein cholesterol in the bloodstream and significantly increases the risk of coronary artery disease. This study aimed to functionally characterize <i>LDLR</i> variants identified in Polish FH patients. Experimental data were used to learn about variants' phenotypes and incorporate them into the ACMG/AMP variant classification framework.<h4>Methods</h4>The functional analysis was performed using the HEK293T-<i>ldlr</i>G1 cells with the expression vectors pTetRedLDLR carrying the mutated <i>LDLR</i> gene variants. Receptor expression was evaluated using Western blot and immunofluorescence. The low-density lipoprotein uptake and ligand binding capacity were examined with fluorescent dye-labeled LDL by confocal microscopy. A functional study was performed to analyze the variants under assessment and compare them to known benign and pathogenic control variants.<h4>Results</h4>The experimental study revealed an impaired activity of the c.662A > G p. (Asp221Gly), c.1775G > A p. (Gly592Glu), and c.2483delA p. (Tyr828Phefs∗101) <i>LDLR</i> variants, classifying them as functionally abnormal. In contrast, <i>in vitro</i> activity assessment of the c.91G > A p. (Glu31Lys) <i>LDLR</i> variant showed fully functional low-density lipoprotein binding and uptake activities. These results suggested that c.91G > A p. (Glu31Lys) is unlikely to be a disease-causing variant.<h4>Conclusions</h4>The results provide functional evidence for the activity of selected <i>LDLR</i> variants in a cellular model based on confocal techniques that meets the ACMG/AMP variant classification criteria. These findings highlight the importance of <i>in vitro</i> assays in evaluating the functional impact of <i>LDLR</i> variants and contribute valuable insights for clinical interpretation and genetic counseling.Atherosclerosis plus30-37https://www.ebi.ac.uk/biostudies/studies/S-EPMC12681971biostudies-literatureCharacterization of selected LDLR substitutions in patients with familial hypercholesterolemia.PMC12681971Waleron KTargonska MJanaszak-Jasiecka AChmara MZuk MKalinowski LWasag BJasiecki JfalseCharacterization of selected LDLR substitutions in patients with familial hypercholesterolemia.<h4>Background and aims</h4>Familial hypercholesterolemia is a genetic disorder caused by pathogenic or likely pathogenic variants in four key genes: <i>LDLR</i>, <i>APOB</i>, <i>PCSK9,</i> and <i>APOE</i>. It leads to elevated levels of low-density lipoprotein cholesterol in the bloodstream and significantly increases the risk of coronary artery disease. This study aimed to functionally characterize <i>LDLR</i> variants identified in Polish FH patients. Experimental data were used to learn about variants' phenotypes and incorporate them into the ACMG/AMP variant classification framework.<h4>Methods</h4>The functional analysis was performed using the HEK293T-<i>ldlr</i>G1 cells with the expression vectors pTetRedLDLR carrying the mutated <i>LDLR</i> gene variants. Receptor expression was evaluated using Western blot and immunofluorescence. The low-density lipoprotein uptake and ligand binding capacity were examined with fluorescent dye-labeled LDL by confocal microscopy. A functional study was performed to analyze the variants under assessment and compare them to known benign and pathogenic control variants.<h4>Results</h4>The experimental study revealed an impaired activity of the c.662A > G p. (Asp221Gly), c.1775G > A p. (Gly592Glu), and c.2483delA p. (Tyr828Phefs∗101) <i>LDLR</i> variants, classifying them as functionally abnormal. In contrast, <i>in vitro</i> activity assessment of the c.91G > A p. (Glu31Lys) <i>LDLR</i> variant showed fully functional low-density lipoprotein binding and uptake activities. These results suggested that c.91G > A p. (Glu31Lys) is unlikely to be a disease-causing variant.<h4>Conclusions</h4>The results provide functional evidence for the activity of selected <i>LDLR</i> variants in a cellular model based on confocal techniques that meets the ACMG/AMP variant classification criteria. These findings highlight the importance of <i>in vitro</i> assays in evaluating the functional impact of <i>LDLR</i> variants and contribute valuable insights for clinical interpretation and genetic counseling.2025-01-01T00:00:00Z2025 Dec2026-06-05T23:52:11.963Z2026-05-23T03:13:53.019ZS-EPMC126819714136284310.1016/j.athplu.2025.11.001