9-132902667-T-C

Variant names:

• chr9-132902667-T-C
• rs1554814968
• NM_000368.5:c.2329A>G

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BS2_Supporting

The NM_000368.5(TSC1):​c.2329A>G​(p.Ser777Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,874 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: TSC1 NM_000368.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 3.07

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]

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=0.24591437).
• BS2: High AC in GnomAdExome4 at 5 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC1	NM_000368.5	c.2329A>G	p.Ser777Gly	missense_variant	Exon 18 of 23	ENST00000298552.9	NP_000359.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC1	ENST00000298552.9	c.2329A>G	p.Ser777Gly	missense_variant	Exon 18 of 23	1	NM_000368.5	ENSP00000298552.3
TSC1	ENST00000490179.4	c.2329A>G	p.Ser777Gly	missense_variant	Exon 19 of 24	3		ENSP00000495533.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461874 Hom.: 0 Cov.: 32 AF XY: 0.00000688 AC XY: 5 AN XY: 727238

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: 0.00000450

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Mar 01, 2024

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 18466115) -

Tuberous sclerosis 1 Uncertain:1

Jun 05, 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 glycine, which is neutral and non-polar, at codon 777 of the TSC1 protein (p.Ser777Gly). 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: 466074). 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 TSC1 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. -

Hereditary cancer-predisposing syndrome Uncertain:1

Oct 09, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.S777G variant (also known as c.2329A>G), located in coding exon 16 of the TSC1 gene, results from an A to G substitution at nucleotide position 2329. The serine at codon 777 is replaced by glycine, an amino acid with similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.091
BayesDel_addAF	Benign	0.0065	T
BayesDel_noAF	Benign	-0.23
CADD	Benign	23
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.50	D;.;D;.;.;D;.;D;.;.;.
Eigen	Uncertain	0.31
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Uncertain	0.88	D
LIST_S2	Uncertain	0.86	.;D;T;D;D;.;.;.;T;D;.
M_CAP	Benign	0.084	D
MetaRNN	Benign	0.25	T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	-0.11	T
MutationAssessor	Benign	1.0	L;.;L;.;.;L;.;L;.;.;.
PrimateAI	Uncertain	0.51	T
PROVEAN	Benign	-1.7	N;N;N;.;.;.;.;.;.;.;.
REVEL	Uncertain	0.40
Sift	Benign	0.21	T;T;T;.;.;.;.;.;.;.;.
Sift4G	Uncertain	0.046	D;D;D;.;.;.;.;.;.;.;.
Polyphen		0.99	D;.;D;.;.;D;.;D;.;.;.
Vest4		0.44
MutPred		0.17		Loss of MoRF binding (P = 0.1028);.;Loss of MoRF binding (P = 0.1028);.;.;Loss of MoRF binding (P = 0.1028);.;Loss of MoRF binding (P = 0.1028);.;.;.;
MVP		0.80
MPC		0.46
ClinPred		0.79	D
GERP RS		4.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.24
gMVP		0.16

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: rs1554814968; hg19: chr9-135778054;