16-2071908-C-G

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 4P and 2B. PM1PM2BP4_Moderate

The NM_000548.5(TSC2):​c.2071C>G​(p.Arg691Gly) 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. 13/22 in silico tools predict 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. R691H) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 33)

Consequence

TSC2
NM_000548.5 missense

Scores

4
15

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:6

Conservation

PhyloP100: 0.491

Publications

4 publications found
Variant links:
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]
TSC2 Gene-Disease associations (from GenCC):
  • tuberous sclerosis
    Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
  • tuberous sclerosis 2
    Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp, Ambry Genetics
  • lymphangioleiomyomatosis
    Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
  • tuberous sclerosis complex
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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

PM1
In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 8 benign, 34 uncertain in NM_000548.5
PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (MetaRNN=0.14491683).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TSC2NM_000548.5 linkc.2071C>G p.Arg691Gly missense_variant Exon 19 of 42 ENST00000219476.9 NP_000539.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TSC2ENST00000219476.9 linkc.2071C>G p.Arg691Gly missense_variant Exon 19 of 42 5 NM_000548.5 ENSP00000219476.3

Frequencies

GnomAD3 genomes
Cov.:
33
GnomAD2 exomes
AF:
0.00
AC:
0
AN:
211208
AF XY:
0.00
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 FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
Cov.:
33
GnomAD4 genome
Cov.:
33

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:6
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:2
Jan 02, 2025
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 691 of the TSC2 protein (p.Arg691Gly). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TSC2-related conditions. ClinVar contains an entry for this variant (Variation ID: 467920). 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 TSC2 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. -

Nov 07, 2021
Genome-Nilou Lab
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Tuberous sclerosis syndrome Uncertain:1
Aug 15, 2023
All of Us Research Program, National Institutes of Health
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This missense variant replaces arginine with glycine at codon 691 of the TSC2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with tuberous sclerosis complex 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. -

not provided Uncertain:1
Jul 01, 2019
GeneDx
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Not observed in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Isolated focal cortical dysplasia type II Uncertain:1
Jan 09, 2024
Baylor Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:1
Feb 23, 2024
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The p.R691G variant (also known as c.2071C>G), located in coding exon 18 of the TSC2 gene, results from a C to G substitution at nucleotide position 2071. The arginine at codon 691 is replaced by glycine, an amino acid with dissimilar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. Based on the available evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.070
BayesDel_addAF
Uncertain
0.032
T
BayesDel_noAF
Benign
-0.19
CADD
Benign
11
DANN
Benign
0.96
DEOGEN2
Uncertain
0.60
D;.;.;.;.;.;.;.;.;.;.;.;D;.;D
Eigen
Benign
-0.78
Eigen_PC
Benign
-0.59
FATHMM_MKL
Benign
0.67
D
LIST_S2
Benign
0.79
T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
M_CAP
Uncertain
0.12
D
MetaRNN
Benign
0.14
T;T;T;T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM
Benign
-0.78
T
MutationAssessor
Benign
-0.90
N;.;.;.;N;N;.;.;.;N;.;N;.;.;.
PhyloP100
0.49
PrimateAI
Benign
0.47
T
PROVEAN
Benign
-1.8
N;.;.;N;.;N;.;.;N;N;.;.;.;.;N
REVEL
Uncertain
0.38
Sift
Benign
0.19
T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Sift4G
Benign
0.48
T;.;.;T;.;T;.;.;T;T;.;.;.;.;T
Polyphen
0.0010
B;.;.;.;B;B;.;.;B;B;.;.;.;.;.
Vest4
0.23
MutPred
0.62
Loss of MoRF binding (P = 0.0376);Loss of MoRF binding (P = 0.0376);Loss of MoRF binding (P = 0.0376);.;Loss of MoRF binding (P = 0.0376);Loss of MoRF binding (P = 0.0376);Loss of MoRF binding (P = 0.0376);Loss of MoRF binding (P = 0.0376);.;Loss of MoRF binding (P = 0.0376);Loss of MoRF binding (P = 0.0376);Loss of MoRF binding (P = 0.0376);Loss of MoRF binding (P = 0.0376);Loss of MoRF binding (P = 0.0376);.;
MVP
0.87
ClinPred
0.16
T
GERP RS
1.0
Varity_R
0.19
gMVP
0.34
Mutation Taster
=98/2
polymorphism

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

Other links and lift over

dbSNP: rs760489473; hg19: chr16-2121909; API