rs876658600

Variant names:

• chr9-132897221-C-T
• rs876658600
• NM_000368.5:c.2938G>A

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_000368.5(TSC1):​c.2938G>A​(p.Glu980Lys) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. E980E) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TSC1 NM_000368.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 5.32
• Publications: 0 publications found

Genes affected

TSC1 (HGNC:12362): (TSC complex subunit 1) This gene is a tumor suppressor gene that encodes the growth inhibitory protein hamartin. The encoded protein interacts with and stabilizes the GTPase activating protein tuberin. This hamartin-tuberin complex negatively regulates mammalian target of rapamycin complex 1 (mTORC1) signaling which is a major regulator of anabolic cell growth. This protein also functions as a co-chaperone for Hsp90 that inhibits its ATPase activity. This protein functions as a facilitator of Hsp90-mediated folding of kinase and non-kinase clients, including TSC2 and thereby preventing their ubiquitination and proteasomal degradation. Mutations in this gene have been associated with tuberous sclerosis and lymphangioleiomyomatosis. [provided by RefSeq, May 2022]

TSC1 Gene-Disease associations (from GenCC):

• tuberous sclerosis

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• tuberous sclerosis 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, PanelApp Australia, Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae)
• lung lymphangioleiomyomatosis

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• tuberous sclerosis complex

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC1	NM_000368.5	c.2938G>A	p.Glu980Lys	missense_variant	Exon 22 of 23	ENST00000298552.9	NP_000359.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC1	ENST00000298552.9	c.2938G>A	p.Glu980Lys	missense_variant	Exon 22 of 23	1	NM_000368.5	ENSP00000298552.3
TSC1	ENST00000490179.4	c.2938G>A	p.Glu980Lys	missense_variant	Exon 23 of 24	3		ENSP00000495533.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 1 Uncertain:2

Oct 20, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 980 of the TSC1 protein (p.Glu980Lys). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TSC1-related conditions. ClinVar contains an entry for this variant (Variation ID: 230504). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt TSC1 protein function with a negative predictive value of 95%. RNA analysis performed to evaluate the impact of this missense change on mRNA splicing indicates it does not significantly alter splicing (internal data). 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. -

Nov 07, 2021

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Uncertain:1

-

Breakthrough Genomics, Breakthrough Genomics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: not provided

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Feb 24, 2015

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.E980K variant (also known as c.2938G>A), located in coding exon 20 of the TSC1 gene, results from a G to A substitution at nucleotide position 2938. The glutamic acid at codon 980 is replaced by lysine, an amino acid with similar properties. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6503 samples (13006 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.06% (greater than 1800 alleles tested) in our clinical cohort. Based on protein sequence alignment, this amino acid position is 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 p.E980K remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.088
BayesDel_addAF	Uncertain	0.067	T
BayesDel_noAF	Benign	-0.14
CADD	Benign	22
DANN	Uncertain	0.99
DEOGEN2	Benign	0.37	T;.;T;.;.;T;.;T;.;.;.
Eigen	Uncertain	0.25
Eigen_PC	Uncertain	0.37
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.93	.;D;D;D;D;.;.;.;D;D;.
M_CAP	Benign	0.084	D
MetaRNN	Benign	0.24	T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	-0.27	T
MutationAssessor	Uncertain	2.1	M;.;M;.;.;M;.;M;.;.;.
PhyloP100		5.3
PrimateAI	Benign	0.37	T
PROVEAN	Benign	-0.32	N;N;N;.;.;.;.;.;.;.;.
REVEL	Uncertain	0.33
Sift	Benign	0.051	T;T;T;.;.;.;.;.;.;.;.
Sift4G	Benign	0.58	T;T;T;.;.;.;.;.;.;.;.
Polyphen		0.20	B;.;B;.;.;B;.;B;.;.;.
Vest4		0.30
MutPred		0.23		Gain of ubiquitination at E980 (P = 0.0203);.;Gain of ubiquitination at E980 (P = 0.0203);.;.;Gain of ubiquitination at E980 (P = 0.0203);.;Gain of ubiquitination at E980 (P = 0.0203);.;.;.;
MVP		0.58
MPC		0.71
ClinPred		0.80	D
GERP RS		5.3
Varity_R		0.29
gMVP		0.19
Mutation Taster		=57/43	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.22		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.22		Position offset: -37

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs876658600; hg19: chr9-135772608;