16-2062497-G-C

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1PM2PP3

The NM_000548.5(TSC2):c.1258G>C(p.Glu420Gln) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 3/3 splice prediction tools predicting alterations to normal splicing. 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. E420K) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0 ( 0 hom., cov: 33)

Failed GnomAD Quality Control

Consequence

TSC2
NM_000548.5 missense, splice_region

Scores

Splicing: ADA: 0.9994

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 7.23

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

TSC2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 8 benign, 29 uncertain in NM_000548.5

PM2

Very rare variant in population databases, with high coverage;

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC2	NM_000548.5 link	c.1258G>C	p.Glu420Gln	missense_variant, splice_region_variant	Exon 13 of 42	ENST00000219476.9	NP_000539.2	P49815-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TSC2	ENST00000219476.9 link	c.1258G>C	p.Glu420Gln	missense_variant, splice_region_variant	Exon 13 of 42	5	NM_000548.5	ENSP00000219476.3		P49815-1

Frequencies

GnomAD3 genomes

AF:

0.00

AC:

AN:

152230

Hom.:

Cov.:

Gnomad AFR

AF:

0.00

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

Cov.:

GnomAD4 genome

Data not reliable, filtered out with message: AC0;AS_VQSR

AF:

0.00

AC:

AN:

152230

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74364

African (AFR)

AF:

0.00

AC:

AN:

41462

American (AMR)

AF:

0.00

AC:

AN:

15290

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5202

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10604

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68044

Other (OTH)

AF:

0.00

AC:

AN:

2092

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000113

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Tuberous sclerosis 2

Uncertain:2

Jul 13, 2023

Foundation for Research in Genetics and Endocrinology, FRIGE's Institute of Human Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

A heterozygous missense variant in exon 13 of the TSC2 gene that results in the amino acid substitution of Glutamine for Glutamic acid at codon 420 (p.Glu420Gln) was detected. The p.Glu420Gln variant has not been reported in the 1000 genomes, gnomAD (v3.1) and gnomdAD (v2) databases and has a minor allele frequency of 0.001% in topmed database. The in silico predictions of the variant are probably damaging by PolyPhen-2 (HumDiv) and damaging by SIFT. The reference codon is conserved across species. In summary, the variant meets our criteria to be classified as a variant of uncertain significance. -

Mar 03, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. 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. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. This sequence change replaces glutamic acid, which is acidic and polar, with glutamine, which is neutral and polar, at codon 420 of the TSC2 protein (p.Glu420Gln). 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: 1762397). -

Hereditary cancer-predisposing syndrome

Uncertain:1

Nov 05, 2021

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.E420Q variant (also known as c.1258G>C) is located in coding exon 12 of the TSC2 gene. The glutamic acid at codon 420 is replaced by glutamine, an amino acid with highly similar properties. This change occurs in the first base pair of coding exon 12. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. In silico splice site analysis predicts that this alteration will result in the creation or strengthening of a novel splice acceptor site. RNA studies have demonstrated that this alteration results in a transcript predicted to lead to a protein with an in-frame deletion of 1 amino acid; however, the exact functional impact of the deleted amino acid is unknown at this time (Ambry internal data). 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

0.31

BayesDel_addAF

Pathogenic

0.23

BayesDel_noAF

Uncertain

0.090

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.76

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

Eigen

Pathogenic

0.72

Eigen_PC

Pathogenic

0.69

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.96

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

M_CAP

Pathogenic

0.35

MetaRNN

Uncertain

0.61

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

MetaSVM

Uncertain

0.41

MutationAssessor

Uncertain

2.4

M;.;.;.;M;M;.;.;.;M;.;M;.;.;.

PhyloP100

7.2

PrimateAI

Benign

0.43

PROVEAN

Uncertain

-2.4

N;.;.;N;.;N;.;.;N;N;.;.;.;.;N

REVEL

Uncertain

0.58

Sift

Uncertain

0.015

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

Sift4G

Benign

0.095

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

Polyphen

1.0

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

Vest4

0.57

MutPred

0.28

Gain of catalytic residue at E420 (P = 0.0919);Gain of catalytic residue at E420 (P = 0.0919);Gain of catalytic residue at E420 (P = 0.0919);.;Gain of catalytic residue at E420 (P = 0.0919);Gain of catalytic residue at E420 (P = 0.0919);Gain of catalytic residue at E420 (P = 0.0919);Gain of catalytic residue at E420 (P = 0.0919);.;Gain of catalytic residue at E420 (P = 0.0919);Gain of catalytic residue at E420 (P = 0.0919);Gain of catalytic residue at E420 (P = 0.0919);Gain of catalytic residue at E420 (P = 0.0919);Gain of catalytic residue at E420 (P = 0.0919);.;

MVP

0.93

ClinPred

0.96

GERP RS

5.2

PromoterAI

0.0057

Neutral

(source)

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.24

gMVP

0.50

Mutation Taster

=58/42

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.99

SpliceAI score (max)

0.79

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.79

Position offset: 3

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over