rs745418679

chr17-43092035-C-Gchr17-43092035-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_007294.4(BRCA1):c.3496G>C(p.Ala1166Pro) 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 1,461,772 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A1166D) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BRCA1 NM_007294.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4 B:1
• Conservation: PhyloP100: 0.865

Genes affected

BRCA1 (HGNC:1100): (BRCA1 DNA repair associated) This gene encodes a 190 kD nuclear phosphoprotein that plays a role in maintaining genomic stability, and it also acts as a tumor suppressor. The BRCA1 gene contains 22 exons spanning about 110 kb of DNA. The encoded protein combines with other tumor suppressors, DNA damage sensors, and signal transducers to form a large multi-subunit protein complex known as the BRCA1-associated genome surveillance complex (BASC). This gene product associates with RNA polymerase II, and through the C-terminal domain, also interacts with histone deacetylase complexes. This protein thus plays a role in transcription, DNA repair of double-stranded breaks, and recombination. Mutations in this gene are responsible for approximately 40% of inherited breast cancers and more than 80% of inherited breast and ovarian cancers. Alternative splicing plays a role in modulating the subcellular localization and physiological function of this gene. Many alternatively spliced transcript variants, some of which are disease-associated mutations, have been described for this gene, but the full-length natures of only some of these variants has been described. A related pseudogene, which is also located on chromosome 17, has been identified. [provided by RefSeq, May 2020]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.3605771).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA1	NM_007294.4	c.3496G>C	p.Ala1166Pro	missense_variant	10/23	ENST00000357654.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA1	ENST00000357654.9	c.3496G>C	p.Ala1166Pro	missense_variant	10/23	1	NM_007294.4	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251294 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135824

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461772 Hom.: 0 Cov.: 39 AF XY: 0.00000138 AC XY: 1 AN XY: 727188

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

ExAC AF: 0.00000824 AC: 1

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Feb 16, 2021	Not observed at a significant frequency in large population cohorts (Lek 2016); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; Also known as 3615G>C -
Uncertain significance, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Jan 22, 2020	The BRCA1 c.3496G>C; p.Ala1166Pro variant (rs745418679), to our knowledge, is not reported in the medical literature but is reported in ClinVar (Variation ID: 216663). This variant is found on a single chromosome in the Genome Aggregation Database (1/251294 alleles), indicating it is not a common polymorphism. The alanine at codon 1166 is moderately conserved, but computational analyses (SIFT: damaging, PolyPhen-2: benign) predict conflicting effects of this variant on protein structure/function. However, due to limited information, the clinical significance of the p.Ala1166Pro variant is uncertain at this time. -

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

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). -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Aug 29, 2023	The p.A1166P variant (also known as c.3496G>C), located in coding exon 9 of the BRCA1 gene, results from a G to C substitution at nucleotide position 3496. The alanine at codon 1166 is replaced by proline, an amino acid with highly similar properties. This alteration was identified in a cohort of 524 Chinese breast cancer patients (Chen B et al. Aging (Albany NY), 2020 Feb;12:3140-3155). This amino acid position is not well 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. -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Feb 21, 2015

In summary, this is a missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been published in the literature and has only been reported once in population databases (no rsID). This sequence change replaces alanine with proline at codon 1166 of the BRCA1 protein (p.Ala1166Pro). The alanine residue is moderately conserved and there is a small physicochemical difference between alanine and proline. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Uncertain	0.11	D
BayesDel_noAF	Uncertain	-0.070
Cadd	Benign	17
Dann	Uncertain	0.99
DEOGEN2	Uncertain	0.54	D;.;.;.
Eigen	Benign	-0.40
Eigen_PC	Benign	-0.57
FATHMM_MKL	Benign	0.24	N
LIST_S2	Benign	0.84	T;T;T;T
M_CAP	Pathogenic	0.30	D
MetaRNN	Benign	0.36	T;T;T;T
MetaSVM	Benign	-0.43	T
MutationAssessor	Uncertain	2.4	M;M;.;.
MutationTaster	Benign	1.0	N;N;N;N;N;N;N;N;N;N;N;N;N;N
PrimateAI	Benign	0.29	T
PROVEAN	Uncertain	-3.5	D;D;D;D
REVEL	Uncertain	0.48
Sift	Uncertain	0.0040	D;D;D;D
Sift4G	Uncertain	0.015	D;D;D;D
Polyphen		0.37	B;.;.;D
Vest4		0.35
MutPred		0.28		Gain of relative solvent accessibility (P = 0.0479);Gain of relative solvent accessibility (P = 0.0479);.;Gain of relative solvent accessibility (P = 0.0479);
MVP		0.68
MPC		0.47
ClinPred		0.67	D
GERP RS		-0.32
Varity_R		0.22
gMVP		0.11

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: rs745418679; hg19: chr17-41244052;