rs786203420

Positions:

• chr2-214780606-T-G
• chr2-214780606-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000465.4(BARD1):​c.1268A>C​(p.Lys423Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. K423R) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: BARD1 NM_000465.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 2.02

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 4 ACMG points.

• PM1: In a cross_link Glycyl lysine isopeptide (Lys-Gly) (interchain with G-Cter in SUMO2) (size 0) in uniprot entity BARD1_HUMAN
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BARD1	NM_000465.4	c.1268A>C	p.Lys423Thr	missense_variant	4/11	ENST00000260947.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BARD1	ENST00000260947.9	c.1268A>C	p.Lys423Thr	missense_variant	4/11	1	NM_000465.4	P2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 12, 2023

The p.K423T variant (also known as c.1268A>C), located in coding exon 4 of the BARD1 gene, results from an A to C substitution at nucleotide position 1268. The lysine at codon 423 is replaced by threonine, an amino acid with similar properties. This amino acid position is conserved. 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

Invitae

Aug 18, 2023

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. 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. ClinVar contains an entry for this variant (Variation ID: 1430149). This variant has not been reported in the literature in individuals affected with BARD1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces lysine, which is basic and polar, with threonine, which is neutral and polar, at codon 423 of the BARD1 protein (p.Lys423Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.50
BayesDel_addAF	Uncertain	0.041	T
BayesDel_noAF	Benign	-0.18
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.30	T;.
Eigen	Uncertain	0.51
Eigen_PC	Uncertain	0.49
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.86	D;D
M_CAP	Uncertain	0.10	D
MetaRNN	Uncertain	0.64	D;D
MetaSVM	Uncertain	-0.25	T
MutationAssessor	Uncertain	2.5	M;.
MutationTaster	Benign	0.98	D;D
PrimateAI	Uncertain	0.54	T
PROVEAN	Uncertain	-3.7	D;.
REVEL	Uncertain	0.33
Sift	Uncertain	0.0030	D;.
Sift4G	Uncertain	0.0090	D;D
Polyphen		0.99	D;.
Vest4		0.55
MutPred		0.42		Loss of methylation at K423 (P = 0.002);.;
MVP		0.95
MPC		0.31
ClinPred		0.99	D
GERP RS		5.2
Varity_R		0.40
gMVP		0.62

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr2-215645330;