16-2087894-C-T

Position:

chr16-2087894-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1PM2

The NM_000548.5(TSC2):c.5021C>T(p.Thr1674Ile) variant causes a missense change. The variant allele was found at a frequency of 0.00000124 in 1,611,868 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. T1674P) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

TSC2
NM_000548.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 4.23

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 links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 4 ACMG points.

PM1

In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 9 benign, 14 uncertain in NM_000548.5

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TSC2	NM_000548.5 linkuse as main transcript	c.5021C>T	p.Thr1674Ile	missense_variant	39/42	ENST00000219476.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TSC2	ENST00000219476.9 linkuse as main transcript	c.5021C>T	p.Thr1674Ile	missense_variant	39/42	5	NM_000548.5		P49815-1

Frequencies

GnomAD3 genomes

AF:

0.00000659

AC:

AN:

151840

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000243

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

6.85e-7

AC:

AN:

1460028

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726300

show subpopulations

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:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000659

AC:

AN:

151840

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74168

show subpopulations

Gnomad4 AFR

AF:

0.0000243

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Tuberous sclerosis 2

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 14, 2023	This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 1674 of the TSC2 protein (p.Thr1674Ile). 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: 468131). 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 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jun 21, 2019

Not observed in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports 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

Jul 15, 2023

The p.T1674I variant (also known as c.5021C>T), located in coding exon 38 of the TSC2 gene, results from a C to T substitution at nucleotide position 5021. The threonine at codon 1674 is replaced by isoleucine, an amino acid with similar 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

Benign

0.19

BayesDel_addAF

Pathogenic

0.27

BayesDel_noAF

Pathogenic

0.16

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.91

D;.;.;.;.;.;.;.;.;.;.;.;D;.;D

Eigen

Uncertain

0.26

Eigen_PC

Uncertain

0.31

FATHMM_MKL

Uncertain

0.91

LIST_S2

Uncertain

0.96

D;D;D;D;D;D;D;D;D;D;D;D;D;D;D

M_CAP

Pathogenic

0.43

MetaRNN

Uncertain

0.69

D;D;D;D;D;D;D;D;D;D;D;D;D;D;D

MetaSVM

Pathogenic

0.93

MutationAssessor

Benign

1.9

L;.;.;.;.;.;.;.;.;.;.;.;.;.;.

MutationTaster

Benign

0.89

D;D;D;D;D;D;D

PrimateAI

Uncertain

0.66

PROVEAN

Uncertain

-2.8

D;.;.;D;.;D;.;.;D;D;.;.;.;.;D

REVEL

Pathogenic

0.70

Sift

Benign

0.060

T;.;.;T;.;T;.;.;T;D;.;.;.;.;T

Sift4G

Benign

0.087

T;.;.;T;.;T;.;.;T;T;.;.;.;.;T

Polyphen

1.0

D;.;.;.;B;B;.;.;P;B;.;.;.;.;.

Vest4

0.72

MutPred

0.57

Gain of sheet (P = 0.0344);.;.;.;.;.;.;.;.;.;.;.;.;.;.;

MVP

0.67

ClinPred

0.95

GERP RS

4.6

RBP_binding_hub_radar

0.97

RBP_regulation_power_radar

2.7

Varity_R

0.38

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over