NR_163945.1:n.251G>C

Variant names:

• chr19-11089409-C-G
• rs875989887
• NR_163945.1:n.251G>C

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The NR_163945.1(LDLR-AS1):​n.251G>C variant causes a non coding transcript exon change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: LDLR-AS1 NR_163945.1 non_coding_transcript_exon
• Clinical Significance: Uncertain significance reviewed by expert panel P:1 U:2
• Conservation: PhyloP100: 2.19
• Publications: 6 publications found

Genes affected

LDLR-AS1 (HGNC:54407): (LDLR antisense RNA 1) This gene represents a regulatory lncRNA that overlaps the 5' UTR and coding sequence of the LDLR (low density lipoprotein receptor) gene. This lncRNA overlaps LDLR in the antisense orientation, and has been shown to downregulate production of the low density lipoprotein receptor. [provided by RefSeq, Jul 2019]

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 Gene-Disease associations (from GenCC):

• hypercholesterolemia, familial, 1

  Inheritance: AD, SD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, ClinGen
• homozygous familial hypercholesterolemia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000307752 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.09).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LDLR	NM_000527.5	c.-140C>G		upstream_gene_variant		ENST00000558518.6	NP_000518.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LDLR	ENST00000558518.6	c.-140C>G		upstream_gene_variant		1	NM_000527.5	ENSP00000454071.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0;AS_VQSR AF: 0.00 AC: 0 AN: 514340 Hom.: 0 Cov.: 7 AF XY: 0.00 AC XY: 0 AN XY: 269310

African (AFR) AF: 0.00 AC: 0 AN: 14240

American (AMR) AF: 0.00 AC: 0 AN: 23308

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 14944

East Asian (EAS) AF: 0.00 AC: 0 AN: 31224

South Asian (SAS) AF: 0.00 AC: 0 AN: 50466

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 33004

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 2106

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 316782

Other (OTH) AF: 0.00 AC: 0 AN: 28266

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:2

Revision: reviewed by expert panel

Submissions by phenotype

Hypercholesterolemia, familial, 1 Pathogenic:1 Uncertain:2

Mar 01, 2016

Fundacion Hipercolesterolemia Familiar

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: research

- -

Mar 25, 2016

LDLR-LOVD, British Heart Foundation

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: literature only

- -

Oct 28, 2022

ClinGen Familial Hypercholesterolemia Variant Curation Expert Panel

Significance: Uncertain significance

Review Status: reviewed by expert panel

Collection Method: curation

The NM_000527.4(LDLR):c.-140C>G variant is classified as Uncertain significance - insufficient evidence for Familial Hypercholesterolemia by applying evidence codes (PM2, PS3_supporting) as defined by the ClinGen Familial Hypercholesterolemia Expert Panel LDLR-specific variant curation guidelines (https://doi.org/10.1101/2021.03.17.21252755). The supporting evidence is as follows: PM2_Met : This variant is absent from gnomAD (v2.1.1). PS3_Mderate : Level 3 assay: PMID:21538688, Hep G2 cell, luciferase reporter gene assay. HepG2 transfection experiments resulted in a residual LDLR transcriptional activity of 7%. The authors also performed electrophoresis mobility shift assays (EMSA), with reference to De Castro et al., 2011; PMID 20884100), which assess if a variant alters promoter protein binding properties (rather unspecifically, however). Although, no mention of any validation control or number of repeats in publication source is available, this variant showed a 25% reduction band intensity compared to WT (i.e. some degree of altered binding properties). These results were confirmed by Kircher M et al (PMID: 31395865). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.090
CADD	Benign	22
DANN	Benign	0.97
PhyloP100		2.2
PromoterAI		-0.90	Under-expression
Mutation Taster		=27/273	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs875989887; hg19: chr19-11200085;