rs879254558

chr19-11105423-T-Cchr19-11105423-T-G

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_000527.5(LDLR):c.517T>C(p.Cys173Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,748 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. C173S) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: LDLR NM_000527.5 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7
• Conservation: PhyloP100: 7.91

Genes affected

LDLR (HGNC:6547): (low density lipoprotein receptor) The low density lipoprotein receptor (LDLR) gene family consists of cell surface proteins involved in receptor-mediated endocytosis of specific ligands. The encoded protein is normally bound at the cell membrane, where it binds low density lipoprotein/cholesterol and is taken into the cell. Lysosomes release the cholesterol, which is made available for repression of microsomal enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, the rate-limiting step in cholesterol synthesis. At the same time, a reciprocal stimulation of cholesterol ester synthesis takes place. Mutations in this gene cause the autosomal dominant disorder, familial hypercholesterolemia. Alternate splicing results in multiple transcript variants.[provided by RefSeq, May 2022]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PM1: In a hotspot region, there are 12 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_000527.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr19-11105423-T-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 251273.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.996
• PP5: Variant 19-11105423-T-C is Pathogenic according to our data. Variant chr19-11105423-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 251272.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr19-11105423-T-C is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
LDLR	NM_000527.5	c.517T>C	p.Cys173Arg	missense_variant	4/18	ENST00000558518.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
LDLR	ENST00000558518.6	c.517T>C	p.Cys173Arg	missense_variant	4/18	1	NM_000527.5	P3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461748 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727180

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hypercholesterolemia, familial, 1 Pathogenic:3

Pathogenic, no assertion criteria provided	research	Laboratorium voor Moleculaire Diagnostiek Experimentele Vasculaire Geneeskunde, Academisch Medisch Centrum	-	- -
Likely pathogenic, criteria provided, single submitter	literature only	LDLR-LOVD, British Heart Foundation	Mar 25, 2016	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Robarts Research Institute, Western University	-	- -

Familial hypercholesterolemia Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Nov 21, 2023	This sequence change replaces cysteine, which is neutral and slightly polar, with arginine, which is basic and polar, at codon 173 of the LDLR protein (p.Cys173Arg). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with familial hypercholesterolemia (PMID: 1301956, 11317361, 33740630). This variant is also known as C152R. ClinVar contains an entry for this variant (Variation ID: 251272). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt LDLR protein function with a positive predictive value of 95%. This variant disrupts the p.Cys173 amino acid residue in LDLR. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 9452094, 11462246, 11810272, 25962062). 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. -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Apr 24, 2017	Variant summary: The LDLR c.517T>C (p.Cys173Arg) variant involves the alteration of a conserved nucleotide. 5/5 in silico tools predict a damaging outcome for this variant and LDL receptor activity in fibroblast from compound heterozygote with p.S265R (known DV) was shown to be 5-15% of wt (Hobbs, 1998). Most of the published reports cite the variant as partially defective allele although now functional studies confirming deleterious impact on the protein function solely by the variant of interest have been published at the time of evaluation. The variant is absent from the large control population datasets of ExAC or gnomAD, but has been reported in multiple affected individuals with biochemically and clinically confirmed FH in heterozygous state (Miltiadous, 2001; Mollaki, 2014) and severe FH in compound heterozygosity with a known pathogenic alleles (Hobbs, 1998; Su, 2009). The c.517T>C is considered to be one of the Greek founder mutations. In addition, a clinical diagnostic laboratory/reputable database classified this variant as Pathogenic. Taken together, this variant is classified as Pathogenic. -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Quest Diagnostics Nichols Institute San Juan Capistrano

Oct 27, 2022

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 as a common Greek variant and was identified in multiple individuals affected with familial hypercholesterolemia (PMID: 9544850 (1998), 11317361 (2001), 19837725 (2010), 21925044 (2011), 25463123 (2014), 30108616 (2018)). Functional studies of cultured fibroblasts showed that this variant with a second pathogenic variant retained only 5-15% LDLR activity (PMID: 1301956 (1992)). Based on the available information, this variant is classified as pathogenic. -

Cardiovascular phenotype Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 20, 2023

The c.517T>C (p.C173R) alteration is located in exon 4 (coding exon 4) of the LDLR gene. This alteration results from a T to C substitution at nucleotide position 517, causing the cysteine (C) at amino acid position 173 to be replaced by an arginine (R). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This alteration, also described as C152R and FH-Greece 1, has been reported in multiple individuals with familial hypercholesterolemia (FH) (Whittall, 2010; Diakou, 2011; Jiang, 2016; Wang, 2016). Another alteration at the same codon, c.519C>G (p.C173W), has been described in multiple individuals with FH (Couture, 1998; Morash, 1998; Sturm, 2021). This amino acid position is highly conserved in available vertebrate species. Pathogenic LDLR mutations that result in the substitution or generation of cysteine residues within the cysteine-rich LDLR class A repeats and EGF-like domains are common in familial hypercholesterolemia (FH) (Villéger, 2002). Internal structural analysis indicates this variant eliminates a disulfide bond critical for the structural integrity of the LDLR class A repeat 4 domain (Ambry internal data). This alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.59
Cadd	Uncertain	25
Dann	Uncertain	0.99
DEOGEN2	Pathogenic	0.97	D;.;.;.
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.98	D;D;D;D
M_CAP	Pathogenic	0.73	D
MetaRNN	Pathogenic	1.0	D;D;D;D
MetaSVM	Pathogenic	0.91	D
MutationAssessor	Pathogenic	4.7	H;.;.;H
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.70	T
PROVEAN	Pathogenic	-11	D;D;D;D
Sift	Pathogenic	0.0	D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D
Polyphen		1.0	D;.;.;.
Vest4		0.97
MutPred		0.94		Gain of phosphorylation at S177 (P = 0.1496);Gain of phosphorylation at S177 (P = 0.1496);.;Gain of phosphorylation at S177 (P = 0.1496);
MVP		1.0
MPC		1.1
ClinPred		1.0	D
GERP RS		5.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		1.0
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs879254558; hg19: chr19-11216099;