chr19-11113375-C-G

Position:

• chr19-11113375-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP4 PS4_Supporting

This summary comes from the ClinGen Evidence Repository: The NM_000527.5 (LDLR):c.1284C>G (p.Asn428Lys) variant is classified as Uncertain significance - insufficient evidence for Familial Hypercholesterolemia by applying ACMG/AMP evidence codes PM2, PP4 and PS4_Supporting as defined by the ClinGen Familial Hypercholesterolemia Expert Panel LDLR-specific variant curation guidelines (specification version 1.2) on 23 June 2023.The supporting evidence is as follows:PM2: Variant is absent from gnomAD (gnomAD v2.1.1).PS4_Supporting, PP4: Variant meets PM2 and is identified in at least 5 index cases who fulfill criteria for FH (1 case with total cholesterol >8 mmol/L and family history of hypercholesterolemia or classical clinical stigmata of FH from PMID 11857755 (Bunn et al., 2002), New Zealand; 1 case with total cholesterol >90th percentile and clinical features of FH or family history of early CHD from PMID 11845603 (Vergotine et al., 2001), South Africa; 1 case with DLCN score >=6 from PMID 11810272 (Fouchier et al., 2001), the Netherlands; 1 case with LDL >95th percentile, plus two of: presence of xanthomata, CAD in proband or family history of CAD or high LDL, from PMID 11668640 (Garcia-Garcia et al., 2001) Spain; 1 case with LDLC 6.5 mmol/L, presence of xanthomas, and history of angioplasty or bypass surgery from PMID 11005141 (Khoo et al., 2000), Malaysia. LINK:https://erepo.genome.network/evrepo/ui/classification/CA10585385/MONDO:0007750/013

• Frequency:
  • Genomes: not found (cov: 29)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: LDLR NM_000527.5 missense
• Clinical Significance: Uncertain significance reviewed by expert panel P:6 U:2
• Conservation: PhyloP100: -0.914

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 Uncertain_significance. Variant got 4 ACMG points.

• PS4: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP4: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
LDLR	NM_000527.5	c.1284C>G	p.Asn428Lys	missense_variant	9/18	ENST00000558518.6	NP_000518.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
LDLR	ENST00000558518.6	c.1284C>G	p.Asn428Lys	missense_variant	9/18	1	NM_000527.5	ENSP00000454071	P3

Frequencies

GnomAD3 genomes Cov.: 29

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461714 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727164

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: 0.00

Gnomad4 OTH exome AF: 0.0000331

GnomAD4 genome Cov.: 29

Asia WGS AF: 0.00144 AC: 5 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:6 Uncertain:2

Revision: reviewed by expert panel

Submissions by phenotype

Familial hypercholesterolemia Pathogenic:3 Uncertain:1

Uncertain significance, criteria provided, single submitter	literature only	LDLR-LOVD, British Heart Foundation	Mar 25, 2016	Re-evaluation of ACMG classification, scoring: PM2, PS4_supporting, PP4. PP3 could not be scored as the score of 0.718 is below the threshold of >0.75. At least 5 unrelated cases of confirmed FH carry this variant. Many further cases have been reported, however, the classification of their diagnosis is not well defined, so PS4 moderate or strong could not be scored. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jun 27, 2024	Variant summary: LDLR c.1284C>G (p.Asn428Lys; also known as N407K in the literature) results in a non-conservative amino acid change located in the LDLR class B repeat (IPR000033) domain of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251288 control chromosomes (gnomAD). c.1284C>G has been reported in the literature in both heterozygous and compound heterozygous individuals affected with familial hypercholesterolemia (FH; example: Bunn_2002, Khoo_2000, Razman_2022, Reijman_2023, Rimbert_2022, Sjouke_2015). The variant was also reported to co-occur with another pathogenic APOB variant in an individual who was affected with both FH and familial defective apolipoprotein B-100. This individual had a more severe phenotype than her siblings who carried only one variant (Tai_2001). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 36499307, 36752612, 11005141, 11857755, 35047021, 27919364, 11238294). ClinVar contains an entry for this variant (Variation ID: 251766). Based on the evidence outlined above, the variant was classified as likely pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 18, 2023	This sequence change replaces asparagine, which is neutral and polar, with lysine, which is basic and polar, at codon 428 of the LDLR protein (p.Asn428Lys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with autosomal dominant familial hypercholesterolemia (PMID: 11005141, 11238294, 11668640, 11857755; Invitae). This variant is also known as N407K. ClinVar contains an entry for this variant (Variation ID: 251766). 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. For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Nov 20, 2023	This missense variant replaces asparagine with lysine at codon 428 of the LDLR protein. This variant is also known as p.Asn407Lys in the mature protein. This variant alters a conserved asparagine residue in the LDLR type B repeat 1 of the LDLR protein (a.a. 397-438), where pathogenic missense variants are found enriched (ClinVar-LDLR). Computational prediction tools indicate that this variant has a deleterious impact on protein structure and function. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in more than 10 heterozygous individuals affected with familial hypercholesterolemia (PMID: 11005141, 11668640, 11845603, 11857755, 14508510, 15556094, 21382890, 35047021, 36499307). This variant has also been observed in compound heterozygous state with known pathogenic LDLR variants in two individuals affected with severe homozygous familial hypercholesterolemia, a phenotype expected of having two deleterious LDLR variants (PMID: 36980993; Callis 2000 dissertation, University of the Orange Free State). It has been shown that this variant segregates with disease in multiple heterozygous affected relatives in one family (Callis 2000 dissertation, University of the Orange Free State). This variant has been detected in over 30 Dutch individuals showing modest severity of hypercholesterolemia with mean LDL-C levels in the 75-88th percentile according to the Dutch Lipid Clinic Network criteria (Hartgers 2020 dissertation, University of Amsterdam). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Based on the available evidence, this variant is classified as Likely Pathogenic. -

Hypercholesterolemia, familial, 1 Pathogenic:2 Uncertain:1

Pathogenic, no assertion criteria provided	research	Laboratorium voor Moleculaire Diagnostiek Experimentele Vasculaire Geneeskunde, Academisch Medisch Centrum	-	- -
Uncertain significance, reviewed by expert panel	curation	ClinGen Familial Hypercholesterolemia Variant Curation Expert Panel	Jun 23, 2023	The NM_000527.5 (LDLR):c.1284C>G (p.Asn428Lys) variant is classified as Uncertain significance - insufficient evidence for Familial Hypercholesterolemia by applying ACMG/AMP evidence codes PM2, PP4 and PS4_Supporting as defined by the ClinGen Familial Hypercholesterolemia Expert Panel LDLR-specific variant curation guidelines (specification version 1.2) on 23 June 2023. The supporting evidence is as follows: PM2: Variant is absent from gnomAD (gnomAD v2.1.1). PS4_Supporting, PP4: Variant meets PM2 and is identified in at least 5 index cases who fulfill criteria for FH (1 case with total cholesterol >8 mmol/L and family history of hypercholesterolemia or classical clinical stigmata of FH from PMID 11857755 (Bunn et al., 2002), New Zealand; 1 case with total cholesterol >90th percentile and clinical features of FH or family history of early CHD from PMID 11845603 (Vergotine et al., 2001), South Africa; 1 case with DLCN score >=6 from PMID 11810272 (Fouchier et al., 2001), the Netherlands; 1 case with LDL >95th percentile, plus two of: presence of xanthomata, CAD in proband or family history of CAD or high LDL, from PMID 11668640 (Garcia-Garcia et al., 2001) Spain; 1 case with LDLC 6.5 mmol/L, presence of xanthomas, and history of angioplasty or bypass surgery from PMID 11005141 (Khoo et al., 2000), Malaysia. -
Likely pathogenic, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Oct 02, 2023	This missense variant (also known as p.Asn407Lys in the mature protein) replaces asparagine with lysine at codon 428 in the LDLR type B repeat 1 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). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in more than 10 heterozygous individuals affected with familial hypercholesterolemia (PMID: 11005141, 11668640, 11845603, 11857755, 14508510, 15556094, 21382890, 35047021, 36499307). This variant has also been observed in compound heterozygous state with known pathogenic LDLR variants in two individuals affected with severe homozygous familial hypercholesterolemia, a phenotype expected of having two deleterious LDLR variants (PMID: 36980993; Callis 2000 dissertation, University of the Orange Free State). Heterozygous relatives of one of these individuals were also affected with hypercholesterolemia (Callis 2000 dissertation, University of the Orange Free State). This variant has been detected in over 30 Dutch individuals showing modest severity of hypercholesterolemia with mean LDL-C levels in the 75-88th percentile according to the Dutch Lipid Clinic Network criteria (Hartgers 2020 dissertation, University of Amsterdam). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Based on the available evidence, this variant is classified as Likely Pathogenic. -

Cardiovascular phenotype Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 20, 2023

The c.1284C>G (p.N428K) alteration is located in exon 9 (coding exon 9) of the LDLR gene. This alteration results from a C to G substitution at nucleotide position 1284, causing the asparagine (N) at amino acid position 428 to be replaced by a lysine (K). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This variant (also referred to as p.N407K) has been detected in several unrelated individuals with familial hypercholesterolemia (FH) (Khoo, 2000; Fouchier, 2001; van der Graaf, 2011; García-García, 2001; Bunn, 2002; Rimbert, 2021; Razman, 2022). This variant has also been detected in additional FH and dyslipidemia cohorts (Vergotine, 2001; Murdock, 2021). In one study, this variant co-occurred with an APOB variant in a proband reported to have more severe hypercholesterolemia than relatives with only one variant (Tai, 2001; Taylor, 2010). This amino acid position is highly conserved in available vertebrate species. This alteration is predicted to be tolerated by in silico analysis. Based on the available evidence, this alteration is classified as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.84
BayesDel_addAF	Uncertain	0.072	D
BayesDel_noAF	Benign	-0.13
CADD	Benign	9.8
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.88	D;.;.;.;.;.
Eigen	Benign	-0.39
Eigen_PC	Benign	-0.60
FATHMM_MKL	Benign	0.73	D
LIST_S2	Pathogenic	0.98	D;D;D;D;D;D
M_CAP	Pathogenic	0.74	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D;D
MetaSVM	Uncertain	0.63	D
MutationAssessor	Benign	1.7	L;.;.;.;.;L
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.65	T
PROVEAN	Pathogenic	-5.6	D;D;D;D;D;D
REVEL	Pathogenic	0.72
Sift	Uncertain	0.0010	D;D;D;D;D;D
Sift4G	Uncertain	0.0050	D;D;D;D;D;D
Polyphen		0.96	P;.;.;.;.;.
Vest4		0.80
MutPred		0.90		Gain of methylation at N428 (P = 0.0236);Gain of methylation at N428 (P = 0.0236);.;.;.;Gain of methylation at N428 (P = 0.0236);
MVP		1.0
MPC		0.70
ClinPred		1.0	D
GERP RS		-3.7
Varity_R		0.92
gMVP		0.98

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs368708058; hg19: chr19-11224051;