chr13-32336561-G-A

Position:

• chr13-32336561-G-A

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP6

The NM_000059.4(BRCA2):​c.2206G>A​(p.Ala736Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,764 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:2
• Conservation: PhyloP100: -1.47

Genes affected

BRCA2 (HGNC:1101): (BRCA2 DNA repair associated) Inherited mutations in BRCA1 and this gene, BRCA2, confer increased lifetime risk of developing breast or ovarian cancer. Both BRCA1 and BRCA2 are involved in maintenance of genome stability, specifically the homologous recombination pathway for double-strand DNA repair. The largest exon in both genes is exon 11, which harbors the most important and frequent mutations in breast cancer patients. The BRCA2 gene was found on chromosome 13q12.3 in human. The BRCA2 protein contains several copies of a 70 aa motif called the BRC motif, and these motifs mediate binding to the RAD51 recombinase which functions in DNA repair. BRCA2 is considered a tumor suppressor gene, as tumors with BRCA2 mutations generally exhibit loss of heterozygosity (LOH) of the wild-type allele. [provided by RefSeq, May 2020]

ACMG classification

Verdict is Likely_benign. Variant got -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.08052626).
• BP6: Variant 13-32336561-G-A is Benign according to our data. Variant chr13-32336561-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 182188.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=3}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.2206G>A	p.Ala736Thr	missense_variant	11/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.2206G>A	p.Ala736Thr	missense_variant	11/27	5	NM_000059.4	ENSP00000369497	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461764 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727180

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Ambry Genetics	Feb 04, 2021	This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -
Likely benign, criteria provided, single submitter	curation	University of Washington Department of Laboratory Medicine, University of Washington	Mar 23, 2023	Missense variant in a coldspot region where missense variants are very unlikely to be pathogenic (PMID:31911673). -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Apr 30, 2024

Variant summary: BRCA2 c.2206G>A (p.Ala736Thr) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 6.8e-07 in 1461764 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.2206G>A in individuals affected with Hereditary Breast And Ovarian Cancer Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 182188). Based on the evidence outlined above, the variant was classified as uncertain significance. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jan 05, 2015

This variant is denoted BRCA2 c.2206G>A at the cDNA level, p.Ala736Thr (A736T) at the protein level, and results in the change of an Alanine to a Threonine (GCA>ACA). This variant has not, to our knowledge, been published in the literature as pathogenic or benign. BRCA2 Ala736Thr was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Sinc Alanine and Threonine differ in polarity, charge, size or other properties, this is considered a non-conservative amino acid substitution. BRCA2 Ala736Thr occurs at a position that is variable across species and is located within the region of interaction with NPM1 (UniProt). In silico analyses predict that this variant is unlikely to alter protein structure or function. Based on currently available information, it is unclear whether BRCA2 Ala736Thr is pathogenic or benign. We consider it to be a variant of uncertain significance. -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 27, 2023

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 736 of the BRCA2 protein (p.Ala736Thr). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with BRCA2-related conditions. ClinVar contains an entry for this variant (Variation ID: 182188). 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 not expected to disrupt BRCA2 protein function with a negative predictive value of 95%. 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	0.075
BayesDel_addAF	Benign	-0.14	T
BayesDel_noAF	Benign	-0.44
CADD	Benign	0.012
DANN	Benign	0.60
Eigen	Benign	-1.7
Eigen_PC	Benign	-1.8
FATHMM_MKL	Benign	0.028	N
M_CAP	Benign	0.018	T
MetaRNN	Benign	0.081	T;T
MetaSVM	Benign	-0.97	T
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.20	T
PROVEAN	Benign	-1.8	N;N
REVEL	Benign	0.12
Sift	Benign	0.25	T;T
Sift4G	Benign	0.64	T;T
Vest4		0.21
MutPred		0.20		Gain of relative solvent accessibility (P = 0.09);Gain of relative solvent accessibility (P = 0.09);
MVP		0.68
MPC		0.022
ClinPred		0.085	T
GERP RS		-7.2
gMVP		0.12

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

LitVar

Other links and lift over

dbSNP: rs730881513; hg19: chr13-32910698;