19-11110664-G-T

Position:

• chr19-11110664-G-T

Variant summary

Our verdict is Pathogenic. Variant got 20 ACMG points: 20P and 0B. PS1_Moderate PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_000527.5(LDLR):​c.953G>T​(p.Cys318Phe) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another nucleotide change resulting in same amino acid change has been previously reported as Likely pathogenicin UniProt. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C318R) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: LDLR NM_000527.5 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8
• Conservation: PhyloP100: 9.68

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]

LDLR (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 20 ACMG points.

• PS1: Transcript NM_000527.5 (LDLR) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in UniProt
• PM1: In a helix (size 2) in uniprot entity LDLR_HUMAN there are 6 pathogenic changes around while only 0 benign (100%) 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 chr19-11110663-T-C is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.994
• PP5: Variant 19-11110664-G-T is Pathogenic according to our data. Variant chr19-11110664-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 251572.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr19-11110664-G-T is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
LDLR	NM_000527.5	c.953G>T	p.Cys318Phe	missense_variant	7/18	ENST00000558518.6	NP_000518.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
LDLR	ENST00000558518.6	c.953G>T	p.Cys318Phe	missense_variant	7/18	1	NM_000527.5	ENSP00000454071.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hypercholesterolemia, familial, 1 Pathogenic:5

Likely pathogenic, criteria provided, single submitter	clinical testing	Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation	Nov 05, 2016	Disrupt disulfide bridge between Cys318 and Cys329. -
Likely pathogenic, criteria provided, single submitter	research	Fundacion Hipercolesterolemia Familiar	Mar 01, 2016	- -
Likely pathogenic, criteria provided, single submitter	literature only	LDLR-LOVD, British Heart Foundation	Mar 25, 2016	- -
Likely pathogenic, criteria provided, single submitter	research	Laboratory of Genetics and Molecular Cardiology, University of São Paulo	Mar 01, 2016	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Laboratory of molecular diagnosis of dyslipidemias, Università egli studi di Napoli Federico II	May 24, 2021	- -

Familial hypercholesterolemia Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jul 31, 2023	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. ClinVar contains an entry for this variant (Variation ID: 251572). This variant is also known as p.Cys297Phe and/or FH Trieste. This missense change has been observed in individuals with clinical features of familial hypercholesterolemia (PMID: 8168830, 23375686, 32770674). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces cysteine, which is neutral and slightly polar, with phenylalanine, which is neutral and non-polar, at codon 318 of the LDLR protein (p.Cys318Phe). This variant affects a cysteine residue located within an LDLRA or epidermal-growth-factor (EGF)-like domains of the LDLR protein. Cysteine residues in these domains have been shown to be involved in the formation of disulfide bridges, which are critical for protein structure and stability (PMID: 7548065, 7603991, 7979249). In addition, missense substitutions within the LDLRA and EGF-like domains affecting cysteine residues are overrepresented among patients with hypercholesterolemia (PMID: 18325082). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Apr 21, 2021	This missense variant replaces cysteine with phenylalanine at codon 318 of the LDLR protein. This variant is also known as p.Cys297Phe in the mature protein and as FH Trieste. This variant is located in the EGF-like repeat A of the EGF precursor homology domain of the LDLR protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). This variant changes one of the functionally critical cysteine residues that form intra-repeat disulfide bonds in the EGF precursor homology domain (PMID: 3495735, 4750422) and is expected to have deleterious impact on the LDLR protein folding and stability. A functional study has shown that the variant causes a significant decrease in LDLR activity (PMID: 8168830). This variant has been reported in the homozygous or compound heterozygous state (PMID: 27578128, 27784735) and in the heterozygous state (PMID: 8168830, 11317362, 15241806, 19446849, 27824480, 28161202, 31993549) in more than 20 individuals affected with familial hypercholesterolemia. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Different missense variants occurring at the same amino acid position, p.Cys318Arg and p.Cys318Tyr, are associated with disease (ClinVar variation ID: 251570, 251571), indicating that cysteine at this position is functionally and clinically important. Based on available evidence, this variant is classified as Pathogenic. -

Cardiovascular phenotype Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 15, 2024

The p.C318F pathogenic mutation (also known as c.953G>T and p.C297F), located in coding exon 7 of the LDLR gene, results from a G to T substitution at nucleotide position 953. The cysteine at codon 318 is replaced by phenylalanine, an amino acid with highly dissimilar properties. 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 L. Hum Mutat. 2002;20(2):81-7). Internal structural analysis indicates this variant eliminates a disulfide bond critical for the structural integrity of the EGF-like 1 domain (Ambry internal data). This variant (also referred to as p.C297F and FH-Trieste) has been observed to segregate with disease in numerous unrelated Italian families affected with FH (Lelli N et al. Hum. Genet. 1994;93(5):538-40, Mozas P et al. Hum. Mutat. 2004;24(2):187, Bertolini S et al. Atherosclerosis 2013;227(2):342-8). Another variant at the same codon, p.C318Y (c.953G>A, also referred to as p.C297Y), has also been reported in association with FH (Hobbs HH et al. Hum Mutat, 1992;1:445-66; Bertolini S et al. Atherosclerosis, 2013 Apr;227:342-8). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the supporting evidence, this variant is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.59	D
BayesDel_noAF	Pathogenic	0.61
CADD	Pathogenic	29
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.94	D;.;.;.;.;.
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.91	D;D;D;D;D;D
M_CAP	Pathogenic	0.82	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.8	H;.;.;.;.;H
PrimateAI	Uncertain	0.59	T
PROVEAN	Pathogenic	-10	D;D;D;D;D;D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D;D;D;D;D;D
Sift4G	Uncertain	0.0020	D;D;D;D;D;D
Polyphen		1.0	D;.;.;.;.;.
Vest4		0.99
MutPred		0.93		Gain of catalytic residue at C318 (P = 0.0012);Gain of catalytic residue at C318 (P = 0.0012);.;.;.;Gain of catalytic residue at C318 (P = 0.0012);
MVP		1.0
MPC		0.75
ClinPred		1.0	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		1.0
gMVP		0.99

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: rs879254739; hg19: chr19-11221340;