chr2-214730494-G-T

Position:

• chr2-214730494-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000465.4(BARD1):​c.1918C>A​(p.Leu640Ile) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,374 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BARD1 NM_000465.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 3.59

Genes affected

BARD1 (HGNC:952): (BRCA1 associated RING domain 1) This gene encodes a protein which interacts with the N-terminal region of BRCA1. In addition to its ability to bind BRCA1 in vivo and in vitro, it shares homology with the 2 most conserved regions of BRCA1: the N-terminal RING motif and the C-terminal BRCT domain. The RING motif is a cysteine-rich sequence found in a variety of proteins that regulate cell growth, including the products of tumor suppressor genes and dominant protooncogenes. This protein also contains 3 tandem ankyrin repeats. The BARD1/BRCA1 interaction is disrupted by tumorigenic amino acid substitutions in BRCA1, implying that the formation of a stable complex between these proteins may be an essential aspect of BRCA1 tumor suppression. This protein may be the target of oncogenic mutations in breast or ovarian cancer. Multiple alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Sep 2013]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BARD1	NM_000465.4	c.1918C>A	p.Leu640Ile	missense_variant	10/11	ENST00000260947.9	NP_000456.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BARD1	ENST00000260947.9	c.1918C>A	p.Leu640Ile	missense_variant	10/11	1	NM_000465.4	ENSP00000260947.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461374 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 726974

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: 0.0000166

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Carcinoma of colon Uncertain:1

Uncertain significance, no assertion criteria provided

in vitro;research

Cancer Genetics Service, National Cancer Centre Singapore

May 01, 2019

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 14, 2023

The p.L640I variant (also known as c.1918C>A), located in coding exon 10 of the BARD1 gene, results from a C to A substitution at nucleotide position 1918. The leucine at codon 640 is replaced by isoleucine, an amino acid with highly similar properties. This variant was seen in 1/1058 patients with colorectal cancer (Yurgelun MB et al. J. Clin. Oncol., 2017 Apr;35:1086-1095). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Familial cancer of breast Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 12, 2024

This sequence change replaces leucine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 640 of the BARD1 protein (p.Leu640Ile). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with colorectal cancer (PMID: 28135145, 31371347). ClinVar contains an entry for this variant (Variation ID: 530056). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Experimental studies have shown that this missense change affects BARD1 function (PMID: 31371347). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Uncertain	0.14	D
BayesDel_noAF	Uncertain	-0.040
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Benign	0.12	T;.;.;.;T;.;.
Eigen	Uncertain	0.51
Eigen_PC	Uncertain	0.49
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Benign	0.77	T;T;T;T;T;.;.
M_CAP	Uncertain	0.13	D
MetaRNN	Uncertain	0.64	D;D;D;D;D;D;D
MetaSVM	Uncertain	-0.0030	T
MutationAssessor	Uncertain	2.1	M;.;.;.;.;.;.
PrimateAI	Uncertain	0.56	T
PROVEAN	Benign	-1.3	N;.;.;.;.;.;N
REVEL	Uncertain	0.42
Sift	Benign	0.047	D;.;.;.;.;.;T
Sift4G	Pathogenic	0.0	D;D;D;D;D;D;D
Polyphen		1.0	D;.;.;.;.;.;.
Vest4		0.56
MutPred		0.56		Loss of catalytic residue at L640 (P = 0.0204);.;.;.;.;.;.;
MVP		0.89
MPC		0.45
ClinPred		0.94	D
GERP RS		4.0
Varity_R		0.33
gMVP		0.41

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1553612535; hg19: chr2-215595218;