rs879255049

Positions:

• chr19-11116999-G-A
• chr19-11116999-G-C
• chr19-11116999-G-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000527.5(LDLR):​c.1845+1G>A variant causes a splice donor 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. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: LDLR NM_000527.5 splice_donor
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:10
• Conservation: PhyloP100: 9.30

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.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 3.1, offset of 11, new splice context is: tacGTacga. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 19-11116999-G-A is Pathogenic according to our data. Variant chr19-11116999-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 252067.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr19-11116999-G-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
LDLR	NM_000527.5	c.1845+1G>A		splice_donor_variant		ENST00000558518.6	NP_000518.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
LDLR	ENST00000558518.6	c.1845+1G>A		splice_donor_variant		1	NM_000527.5	ENSP00000454071	P3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:10

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hypercholesterolemia, familial, 1 Pathogenic:6

Pathogenic, criteria provided, single submitter	clinical testing	Molecular Genetics Laboratory, Centre for Cardiovascular Surgery and Transplantation	Nov 05, 2016	- -
Pathogenic, no assertion criteria provided	research	Laboratorium voor Moleculaire Diagnostiek Experimentele Vasculaire Geneeskunde, Academisch Medisch Centrum	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	U4M - Lille University & CHRU Lille, Université de Lille - CHRU de Lille	Mar 30, 2017	- -
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	-	- -
Pathogenic, criteria provided, single submitter	curation;literature only	Cardiovascular Research Group, Instituto Nacional de Saude Doutor Ricardo Jorge	Mar 01, 2016	- -

Familial hypercholesterolemia Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 02, 2021	For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 252067). Disruption of this splice site has been observed in individuals with familial hypercholesterolemia (PMID: 15556094, 21115573). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change affects a donor splice site in intron 12 of the LDLR gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in LDLR are known to be pathogenic (PMID: 20809525, 28645073). -
Pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Nov 14, 2023	This variant causes a G to A nucleotide substitution at the + 1 canonical donor position of intron 12 of the LDLR gene. Splice site prediction tools suggest that this variant may have a significant impact on RNA splicing. Although this prediction has not been confirmed in published RNA studies, this variant is expected to result in an absent or disrupted protein product. Functional studies using cultured fibroblasts derived from individuals homozygous for this variant and clinically affected with familial hypercholesterolemia have shown that this variant causes a significant reduction in LDL receptor activity (PMID: 1301956, 21115573). This LDLR variant has been reported in at least seven heterozygous individuals affected with familial hypercholesterolemia (PMID: 1301956, 15556094, 21115573, 21310417, 22417841, 27765764, 28645073). This variant has also been observed in compound heterozygous state with a known pathogenic LDLR variant in one individual affected with severe homozygous familial hypercholesterolemia, a phenotype expected of having two deleterious LDLR variants (PMID: 36325061). It has been shown that this variant segregates with disease in multiple affected individuals across two families (PMID: 21115573). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of LDLR function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Mar 12, 2024	Variant summary: LDLR c.1845+1G>A is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Three predict the variant abolishes a 5' splicing donor site. At least one publication reports experimental evidence that this variant affects mRNA splicing (Hobbs_1992). The variant was absent in 251452 control chromosomes (gnomAD). The variant c.1845+1G>A (also known as FH Tunis) has been reported in the literature in multiple homozygous-, compound heterozygous- and heterozygous individuals affected with Familial Hypercholesterolemia, where patients with biallelic variants had a more severe phenotype (e.g. Hobbs_1992, Jelassi_2010, Jelassi_2011, Slimani_2012, Du_2022). These data indicate that the variant is very likely to be associated with disease. Publications also reported experimental evidence evaluating an impact on protein function and demonstrated that this variant resulted in less than 2% LDL receptor activity in fibroblasts derived from homozygous patients (Hobbs_1992, Jelassi_2011). The following publications have been ascertained in the context of this evaluation (PMID: 1301956, 20144596, 21115573, 22417841, 36325061). ClinVar contains an entry for this variant (Variation ID: 252067). Based on the evidence outlined above, the variant was classified as pathogenic. -

Cardiovascular phenotype Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 18, 2022

The c.1845+1G>A intronic pathogenic mutation results from a G to A substitution one nucleotide after coding exon 12 of the LDLR gene. This alteration, also known as FH Tunis, has been reported as heterozygous and homozygous in subjects with familial hypercholesterolemia (FH) (Jelassi A et al. Ann Clin Biochem, 2011 Jan;48:83-6; Laurie AD et al. Atheroscler Suppl, 2004 Dec;5:13-5; Dušková L et al. Atherosclerosis, 2011 May;216:139-45; Wang J et al. Arterioscler Thromb Vasc Biol, 2016 12;36:2439-2445). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). In silico splice site analysis predicts that this alteration will weaken the native splice donor site and may result in the creation or strengthening of a novel splice donor site. In addition to the clinical data presented in the literature, alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.16
CADD	Pathogenic	34
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Pathogenic	0.99	D
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.43		Position offset: 10
DS_DL_spliceai		0.99		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs879255049; hg19: chr19-11227675;