rs45517114

Positions:

• chr16-2055513-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_000548.5(TSC2):​c.593T>C​(p.Met198Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,304 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. M198I) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: TSC2 NM_000548.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5 O:1
• Conservation: PhyloP100: 7.28

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 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.814

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5	c.593T>C	p.Met198Thr	missense_variant	6/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9	c.593T>C	p.Met198Thr	missense_variant	6/42	5	NM_000548.5

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461304 Hom.: 0 Cov.: 30 AF XY: 0.00000413 AC XY: 3 AN XY: 727022

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

Alfa AF: 0.0000530 Hom.: 0

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5 Other:1

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	Invitae	Jul 29, 2023	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. ClinVar contains an entry for this variant (Variation ID: 49375). This missense change has been observed in individual(s) with tuberous sclerosis complex (PMID: 17304050). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces methionine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 198 of the TSC2 protein (p.Met198Thr). -

Tuberous sclerosis syndrome Uncertain:1 Other:1

Uncertain significance, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Jun 26, 2023	This missense variant replaces methionine with threonine at codon 198 of the TSC2 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with TSC2-related disorders 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, no classification provided	curation	Tuberous sclerosis database (TSC2)	-	- -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Jun 23, 2016

Variant identified in a genome or exome case(s) and assessed due to predicted null impact of the variant or pathogenic assertions in the literature or databases. Disclaimer: This variant has not undergone full assessment. The following are preliminary notes: 1 report -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 11, 2024

The p.M198T variant (also known as c.593T>C), located in coding exon 5 of the TSC2 gene, results from a T to C substitution at nucleotide position 593. The methionine at codon 198 is replaced by threonine, an amino acid with similar properties. This alteration was identified in 1 of 506 patients with a definite or probable clinical diagnosis of TSC (Au KS et al. Genet Med, 2007 Feb;9:88-100). This amino acid position is highly conserved in available vertebrate species. 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	0.68
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.27
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.72	D;.;.;.;.;.;.;.;.;.;.;.;T;.;T
Eigen	Uncertain	0.50
Eigen_PC	Uncertain	0.45
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.89	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.65	D
MetaRNN	Pathogenic	0.81	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.33	D
MutationAssessor	Uncertain	2.1	M;.;.;.;M;M;.;.;.;M;.;M;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Uncertain	0.76	T
PROVEAN	Uncertain	-3.1	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
REVEL	Pathogenic	0.82
Sift	Uncertain	0.0040	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Sift4G	Uncertain	0.0030	D;.;.;D;.;D;.;.;D;D;.;.;.;.;D
Polyphen		0.95	P;.;.;.;.;P;.;.;D;P;.;.;.;.;.
Vest4		0.89
MutPred		0.54		Loss of stability (P = 0.1551);Loss of stability (P = 0.1551);Loss of stability (P = 0.1551);.;Loss of stability (P = 0.1551);Loss of stability (P = 0.1551);Loss of stability (P = 0.1551);Loss of stability (P = 0.1551);.;Loss of stability (P = 0.1551);Loss of stability (P = 0.1551);Loss of stability (P = 0.1551);Loss of stability (P = 0.1551);Loss of stability (P = 0.1551);.;
MVP		0.79
ClinPred		0.97	D
GERP RS		4.9
Varity_R		0.61
gMVP		0.79

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: rs45517114; hg19: chr16-2105514;