rs875989906
Variant summary
Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong
The NM_000527.5(LDLR):c.661G>A(p.Asp221Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000617 in 1,459,316 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D221G) has been classified as Likely pathogenic.
Frequency
Consequence
NM_000527.5 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 18 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
---|---|---|---|---|---|---|---|---|
LDLR | NM_000527.5 | c.661G>A | p.Asp221Asn | missense_variant | Exon 4 of 18 | ENST00000558518.6 | NP_000518.1 |
Ensembl
Frequencies
GnomAD3 genomes Cov.: 33
GnomAD4 exome AF: 0.00000617 AC: 9AN: 1459316Hom.: 0 Cov.: 33 AF XY: 0.00000689 AC XY: 5AN XY: 725566
GnomAD4 genome Cov.: 33
ClinVar
Submissions by phenotype
Hypercholesterolemia, familial, 1 Pathogenic:10
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Criteria applied: PS4,PM5_STR,PM2_SUP,PP3 -
The c.661G>A (p.Asp221Asn) variant (also known as p.Asp200Asn) in the LDLR gene, that encodes for low density lipoprotein receptor, has been identified in numerous individuals (>100) affected with Familial Hypercholesterolemia (FH) (PMID: 17094996, 9409298, 25962062, 29399563, 33740630, 17142622, 15199436). This variant has also been reported in homozygous status in an individual with severe FH (total cholesterol >500mg/dL, LDL-C: Unknown) (PMID: 22836070). Experimental studies using patient-derived lymbhoblasts revealed reduced LDLR activity (PMID: 9409298). This variant is located within the well-established LDL binding domain (amino acids 105-232) critical for protein function (PMID: 2600087). Computational prediction tools suggest that the p.Asp221Asn variant may have deleterious effect on the protein function (REVEL score: 0.816). This variant is found to be rare (9/1459316; 0.0006167%) in the general population database, gnomAD v4.0.0 and interpreted as pathogenic by multiple submitters in ClinVar (ID: 226331). Other substitutions affecting the same amino acid position, p.Asp221Tyr (ClinVar ID: 251356) and p.Asp221Gly (ClinVar ID: 183092), have also been reported to be pathogenic by the ClinGen variant curation expert panel. Therefore, the c.661G>A (p.Asp221Asn) variant in LDLR gene is classified as pathogenic. -
subject mutated among 2600 FH index cases screened = 1 / previously described in association with FH / Software predictions: Conflicting -
Asp221 bind structural Ca2+. -
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Familial hypercholesterolemia Pathogenic:5
This missense variant (also known as p.Asp200Asn in the mature protein) replaces aspartic acid with asparagine at codon 221 in the LDLR type A repeat 5 of the LDLR protein. Computational prediction suggests that this variant may have a deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). Experimental functional studies have shown that this variant may disrupt LDLR protein folding due to defective calcium ion binding (PMID: 8784348, 9262405) and result in reduced LDLR activity (PMID: 9409298). This variant has been reported in over 100 individuals affected with familial hypercholesterolemia (PMID: 9409298, 10090484, 11196104, 16250003, 17094996, 24075752, 25962062, 29399563, 33740630, 34456200). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Different missense variants affecting the same codon (p.Asp221Gly, p.Asp221Tyr, Asp221Val) are considered to be disease-causing (ClinVar variation ID: 183092, 251356, 251357), suggesting that aspartic acid at this position is important for LDLR protein function. Based on the available evidence, this variant is classified as Pathogenic. -
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Variant summary: LDLR c.661G>A (p.Asp221Asn), also known as p.Asp200Asn, results in a conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The frequency data for this variant in gnomAD is considered unreliable, as metrics indicate poor data quality at this position. c.661G>A has been reported in the literature in multiple heterozygous individuals and at-least one homozygous individual affected with Familial Hypercholesterolemia (example: Graesdal_2012, Sun_1997, Weiss_2000, Humphries_2006). These data indicate that the variant is very likely to be associated with disease. At least one publication reports the reduced degradation of radiolabeled LDL in cells derived from a patient harboring the variant, suggesting the variant impairs LDL-receptor function (Sun_1997). Furthermore, another missense variant affecting this amino acid (c.662A>G, p.Asp221Gly) has been classified as pathogenic by our laboratory, supporting the critical relevance of codon 221 to LDLR protein function. The following publications have been ascertained in the context of this evaluation (PMID: 22836070, 17142622, 9409298, 11196104). ClinVar contains an entry for this variant (Variation ID: 226331). Based on the evidence outlined above, the variant was classified as pathogenic. -
This sequence change replaces aspartic acid, which is acidic and polar, with asparagine, which is neutral and polar, at codon 221 of the LDLR protein (p.Asp221Asn). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with familial hypercholesterolemia (PMID: 1714262, 11196104, 17094996, 24075752, 25962062). Invitae Evidence Modeling of clinical and family history, age, sex, and reported ancestry of multiple individuals with this LDLR variant has been performed. This variant is expected to be pathogenic with a positive predictive value of at least 99%. This is a validated machine learning model that incorporates the clinical features of 363,995 individuals referred to our laboratory for LDLR testing. This variant is also known as c.661G>A, p.Asp200Asn. ClinVar contains an entry for this variant (Variation ID: 226331). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt LDLR protein function with a positive predictive value of 95%. This variant disrupts the p.Asp221 amino acid residue in LDLR. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 1301956, 19318025, 23375686, 25487149, 25647241). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -
The c.661G>A (p.Asp221Asn) variant in the LDLR gene has been reported in multiple individuals with familial hypercholesterolemia (PMID: 9409298, 10090484, 11196104, 15199436, 15359125, 16250003, 17094996, 24075752, 25962062). The variant is not observed in gnomAD. The allelic change p.Asp221Tyr is an established pathogenic variant for FH. Functional studies demonstrated deleterious effect of the p.Asp221Asn variant. Multiple algorithms predicted this change to be deleterious. Therefore, the c.661G>A (p.Asp221Asn) variant in the LDLR gene is classified as pathogenic. -
not provided Pathogenic:2
This variant has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). In the published literature, the variant has been reported in multiple in individuals with familial hypercholesterolemia (FH) (PMID: 9409298 (1997), 9544745 (1998), 11196104 (2000), 34456200 (2021)), including one homozygous individual (PMID: 17142622 (2006)). It has also been reported in an individual with autosomal dominant hypercholesterolemia (ADH) (PMID: 16250003 (2005)), as well as in an otherwise healthy individual (PMID: 32719484 (2020)). A functional study found this variant was damaging to protein function (PMID: 9409298 (1997)). Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded predictions that this variant is damaging. Based on the available information, this variant is classified as pathogenic. -
Not observed at significant frequency in large population cohorts (gnomAD); Located in a region intolerant to change; In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 22883975, 31447099, 16250003, 10090484, 11196104, 15359125, 19837725, 24075752, 35913489, 9544745, 33955087, 33740630, 32719484, 34037665) -
Cardiovascular phenotype Pathogenic:1
The p.D221N variant (also known as c.661G>A), located in coding exon 4 of the LDLR gene, results from a G to A substitution at nucleotide position 661. The aspartic acid at codon 221 is replaced by asparagine, an amino acid with highly similar properties. This alteration has been reported in a number of individuals with familial hypercholesterolemia (Sun XM et al. Atherosclerosis, 1998 Jan;136:175-85; Ebhardt M et al. Hum. Mutat., 1999;13:257; Kim JH et al. Mol. Cells, 2004 Aug;18:63-70; Leren TP et al. Semin Vasc Med, 2004 Feb;4:75-85; Fouchier SW et al. Hum. Mutat., 2005 Dec;26:550-6). This alteration has also been reported as homozygous in a subject with tendom xanthomas and a total cholesterol of >500 mg/dL (Græsdal A et al. J Clin Lipidol Mar;6:331-9). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at