17-43115754-A-T

Variant names:

• chr17-43115754-A-T
• rs905812561
• NM_007294.4:c.106T>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM1 PM2 BP6

The NM_007294.4(BRCA1):​c.106T>A​(p.Ser36Thr) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,458 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. S36A) 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:3 B:1
• Conservation: PhyloP100: 4.11
• Publications: 7 publications found

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]

BRCA1 Gene-Disease associations (from GenCC):

• breast-ovarian cancer, familial, susceptibility to, 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, ClinGen, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• Fanconi anemia, complementation group S

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, LIMITED Submitted by: G2P, Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
• pancreatic cancer, susceptibility to, 4

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• hereditary breast ovarian cancer syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Fanconi anemia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM1: In a hotspot region, there are 27 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 12 benign, 73 uncertain in NM_007294.4
• PM2: Very rare variant in population databases, with high coverage
• BP6: Variant 17-43115754-A-T is Benign according to our data. Variant chr17-43115754-A-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 489704.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BRCA1	NM_007294.4	c.106T>A	p.Ser36Thr	missense_variant	Exon 3 of 23	ENST00000357654.9	NP_009225.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BRCA1	ENST00000357654.9	c.106T>A	p.Ser36Thr	missense_variant	Exon 3 of 23	1	NM_007294.4	ENSP00000350283.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461458 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 727020

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44670

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26110

East Asian (EAS) AF: 0.00 AC: 0 AN: 39670

South Asian (SAS) AF: 0.00 AC: 0 AN: 86196

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53390

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111800

Other (OTH) AF: 0.00 AC: 0 AN: 60376

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

Nov 05, 2024

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces serine with threonine at codon 36 of the BRCA1 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function. Functional studies have reported that this variant is functionally normal in a haploid cell proliferation assay, in a ubiquitin ligase assay and BARD1 binding assays (PMID: 25823446, 30209399, 35659930). To our knowledge, this variant has not been reported in individuals affected with BRCA1-related disorders in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance.

Feb 23, 2023

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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.

not provided Uncertain:1

Jan 14, 2022

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The BRCA1 c.106T>A; p.Ser36Thr variant (rs905812561), to our knowledge, is not reported in the medical literature associated with disease but is reported in ClinVar (Variation ID: 489704). This variant is absent from the Genome Aggregation Database, indicating it is not a common polymorphism. The serine at codon 36 is highly conserved, and computational analyses are uncertain whether this variant is neutral or deleterious (REVEL: 0.605). One in vitro functional study demonstrates no significant effect on homology-directed repair activity (Starita 2015). However, given the lack of clinical and functional data, the significance of the p.Ser36Thr variant is uncertain at this time. References: Starita LM et al. Massively Parallel Functional Analysis of BRCA1 RING Domain Variants. Genetics. 2015 Jun;200(2):413-22. PMID: 25823446.

Hereditary breast ovarian cancer syndrome Uncertain:1

Mar 25, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces serine, which is neutral and polar, with threonine, which is neutral and polar, at codon 36 of the BRCA1 protein (p.Ser36Thr). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with BRCA1-related conditions. ClinVar contains an entry for this variant (Variation ID: 489704). Advanced modeling performed at Invitae incorporating data from internal and/or published experimental studies (PMID: 30209399) indicates that this missense variant is not expected to disrupt BRCA1 function with a negative predictive value of 95%. Experimental studies have shown that this missense change does not substantially affect BRCA1 function (PMID: 25823446, 30209399). 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	Uncertain	0.39
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.26
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.0	.;T;.;.;.;T;.;T;T;.;T;T;.
Eigen	Uncertain	0.58
Eigen_PC	Uncertain	0.63
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Benign	0.83	T;T;T;T;T;T;T;T;T;D;T;T;D
M_CAP	Pathogenic	0.39	D
MetaRNN	Uncertain	0.48	T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Pathogenic	0.83	D
MutationAssessor	Benign	-0.59	N;N;N;N;N;.;.;.;.;.;.;.;.
PhyloP100		4.1
PrimateAI	Uncertain	0.71	T
PROVEAN	Benign	-1.5	N;N;N;N;N;N;N;.;N;N;N;N;N
REVEL	Uncertain	0.60
Sift	Benign	0.080	T;D;D;T;T;T;D;.;D;D;D;T;D
Sift4G	Benign	0.22	T;D;D;T;T;.;D;.;D;.;D;.;.
Vest4		0.60
ClinPred		0.88	D
GERP RS		6.0
RBP_binding_hub_radar		0.92
RBP_regulation_power_radar		2.6
Varity_R		0.74
gMVP		0.40

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: rs905812561; hg19: chr17-41267771;