rs397515261

Positions:

• chr16-2062994-C-G
• chr16-2062994-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PM5 PP3_Moderate

The NM_000548.5(TSC2):​c.1384C>G​(p.Arg462Gly) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic 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. R462P) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 4.41

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 Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr16-2062994-C-T is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.909

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.1384C>G	p.Arg462Gly	missense_variant	14/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.1384C>G	p.Arg462Gly	missense_variant	14/42	5	NM_000548.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Tuberous sclerosis 2 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jun 04, 2020	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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has been reported in individuals Leiden Open-source Variation Database (PMID: 21520333). This variant is not present in population databases (ExAC no frequency). This sequence change replaces arginine with glycine at codon 462 of the TSC2 protein (p.Arg462Gly). The arginine residue is highly conserved and there is a moderate physicochemical difference between arginine and glycine. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Dec 04, 2019

Not observed in large population cohorts (Lek et al., 2016); In silico analyses, including protein predictors and evolutionary conservation, support a deleterious effect; Has not been previously published as pathogenic or benign to our knowledge -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 01, 2022

The p.R462G variant (also known as c.1384C>G), located in coding exon 13 of the TSC2 gene, results from a C to G substitution at nucleotide position 1384. The arginine at codon 462 is replaced by glycine, an amino acid with dissimilar properties. This amino acid position is conserved. In addition, this alteration is predicted to be deleterious 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	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.34
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	D;.;.;.;.;.;.;.;.;.;.;.;D;.;D
Eigen	Uncertain	0.46
Eigen_PC	Uncertain	0.50
FATHMM_MKL	Uncertain	0.87	D
LIST_S2	Uncertain	0.97	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.42	D
MetaRNN	Pathogenic	0.91	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.13	D
MutationAssessor	Uncertain	2.7	M;.;.;.;M;M;.;.;.;M;.;M;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.74	T
PROVEAN	Pathogenic	-6.1	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
REVEL	Pathogenic	0.74
Sift	Uncertain	0.0040	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Sift4G	Uncertain	0.032	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Polyphen		0.24	B;.;.;.;B;P;.;.;P;P;.;.;.;.;.
Vest4		0.99
MutPred		0.68		Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);.;Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);.;Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);.;
MVP		0.98
ClinPred		0.95	D
GERP RS		5.2
Varity_R		0.85
gMVP		0.91

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs397515261; hg19: chr16-2112995;