rs776738338

Positions:

• chr16-2081763-C-G
• chr16-2081763-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000548.5(TSC2):​c.3779C>G​(p.Thr1260Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T1260M) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 3.04

Genes affected

TSC2 (HGNC:12363): (TSC complex subunit 2) This gene is a tumor suppressor gene that encodes the growth inhibitory protein tuberin. Tuberin interacts with hamartin to form the TSC protein complex which functions in the control of cell growth. This TSC protein complex negatively regulates mammalian target of rapamycin complex 1 (mTORC1) signaling which is a major regulator of anabolic cell growth. Mutations in this gene have been associated with tuberous sclerosis and lymphangioleiomyomatosis. [provided by RefSeq, May 2022]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.22895092).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TSC2	NM_000548.5	c.3779C>G	p.Thr1260Arg	missense_variant	31/42	ENST00000219476.9	NP_000539.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9	c.3779C>G	p.Thr1260Arg	missense_variant	31/42	5	NM_000548.5	ENSP00000219476

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 10, 2021

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. 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 TSC2 protein function. This variant has not been reported in the literature in individuals affected with TSC2-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces threonine with arginine at codon 1260 of the TSC2 protein (p.Thr1260Arg). The threonine residue is moderately conserved and there is a moderate physicochemical difference between threonine and arginine. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 08, 2024

The p.T1260R variant (also known as c.3779C>G), located in coding exon 30 of the TSC2 gene, results from a C to G substitution at nucleotide position 3779. The threonine at codon 1260 is replaced by arginine, an amino acid with similar properties. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this variant remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Uncertain	0.11	D
BayesDel_noAF	Uncertain	-0.080
CADD	Benign	23
DANN	Benign	0.97
DEOGEN2	Uncertain	0.53	D;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Benign	-0.26
Eigen_PC	Benign	-0.24
FATHMM_MKL	Uncertain	0.88	D
LIST_S2	Uncertain	0.93	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Uncertain	0.24	D
MetaRNN	Benign	0.23	T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	-0.25	T
MutationAssessor	Uncertain	2.0	M;.;.;.;.;.;.;.;.;M;.;.;.;.;.
MutationTaster	Benign	1.0	N;N;N;N;N;N;N
PrimateAI	Benign	0.33	T
PROVEAN	Benign	-1.9	N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL	Uncertain	0.40
Sift	Uncertain	0.0090	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Sift4G	Benign	0.52	T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen		1.0	D;.;.;.;B;P;.;.;B;B;.;.;.;.;.
Vest4		0.30
MutPred		0.19		Loss of glycosylation at T1260 (P = 0.0076);.;Loss of glycosylation at T1260 (P = 0.0076);.;.;.;.;Loss of glycosylation at T1260 (P = 0.0076);.;Loss of glycosylation at T1260 (P = 0.0076);.;.;.;.;.;
MVP		0.85
ClinPred		0.34	T
GERP RS		3.3
Varity_R		0.10
gMVP		0.50

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr16-2131764;