chr16-2072867-C-A

Variant names:

Variant summary

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

The NM_000548.5(TSC2):c.2239C>A(p.Leu747Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,613,538 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. L747Q) has been classified as Uncertain significance.

Frequency

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

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

TSC2
NM_000548.5 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 1.23

Publications

7 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 2 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 9 benign, 15 uncertain in NM_000548.5

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.17095602).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TSC2	NM_000548.5 link	c.2239C>A	p.Leu747Met	missense_variant	Exon 21 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.2239C>A	p.Leu747Met	missense_variant	Exon 21 of 42	5	NM_000548.5	ENSP00000219476.3		P49815-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152238

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.00000137

AC:

AN:

1461300

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726916

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52846

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1112004

Other (OTH)

AF:

0.0000166

AC:

AN:

60388

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.550

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152238

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74372

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.0000241

AC:

AN:

41466

American (AMR)

AF:

0.00

AC:

AN:

15284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68042

Other (OTH)

AF:

0.00

AC:

AN:

2088

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.325

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

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

Oct 10, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces leucine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 747 of the TSC2 protein (p.Leu747Met). 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: 233802). 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

Oct 27, 2023

All of Us Research Program, National Institutes of Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Hereditary cancer-predisposing syndrome

Uncertain:1

Apr 10, 2024

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.L747M variant (also known as c.2239C>A), located in coding exon 20 of the TSC2 gene, results from a C to A substitution at nucleotide position 2239. The leucine at codon 747 is replaced by methionine, an amino acid with highly similar properties. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. 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

0.090

BayesDel_addAF

Uncertain

0.041

BayesDel_noAF

Benign

-0.18

CADD

Benign

(source)

DANN

Benign

0.95

DEOGEN2

Uncertain

0.48

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

Eigen

Benign

-0.53

Eigen_PC

Benign

-0.54

FATHMM_MKL

Benign

0.093

LIST_S2

Uncertain

0.87

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

M_CAP

Uncertain

0.11

MetaRNN

Benign

0.17

T;T;T;T;T;T;T;T;T;T;T;T;T;T;T

MetaSVM

Uncertain

-0.26

MutationAssessor

Benign

1.1

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

PhyloP100

1.2

PrimateAI

Benign

0.38

PROVEAN

Benign

-0.42

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

REVEL

Uncertain

0.32

Sift

Uncertain

0.024

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

Sift4G

Benign

0.24

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

Polyphen

0.81

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

Vest4

0.37

MutPred

0.72

Gain of disorder (P = 0.0995);Gain of disorder (P = 0.0995);Gain of disorder (P = 0.0995);.;Gain of disorder (P = 0.0995);Gain of disorder (P = 0.0995);Gain of disorder (P = 0.0995);Gain of disorder (P = 0.0995);.;Gain of disorder (P = 0.0995);Gain of disorder (P = 0.0995);Gain of disorder (P = 0.0995);Gain of disorder (P = 0.0995);Gain of disorder (P = 0.0995);.;

MVP

0.54

ClinPred

0.056

GERP RS

2.5

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.071

gMVP

0.14

Mutation Taster

=94/6

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

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

Publications

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chr16-2072867-C-A

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over