Genetic Variant NM_000548.5:c.2545A>G (chr16-2074389-A-G) – ACMG Classification: Likely_benign (-5 pts)

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 4P and 9B. PM1PM5BP6BS1BS2

The NM_000548.5(TSC2):c.2545A>G(p.Thr849Ala) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000013 in 1,610,086 control chromosomes in the GnomAD database, with no homozygous occurrence. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T849S) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000011 ( 0 hom. )

Consequence

TSC2
NM_000548.5 missense, splice_region

Scores

Splicing: ADA: 0.6405

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:4

Conservation

PhyloP100: 7.24

Publications

5 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: Likely_benign. The variant received -5 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 6 benign, 36 uncertain in NM_000548.5

PM5

Other missense variant is known to change same aminoacid residue: Variant chr16-2074389-A-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 2068302.Status of the report is criteria_provided_single_submitter, 1 stars.

BP6

Variant 16-2074389-A-G is Benign according to our data. Variant chr16-2074389-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 391969.

BS1

Variant frequency is greater than expected in population mid. GnomAdExome4 allele frequency = 0.000011 (16/1457778) while in subpopulation MID AF = 0.000876 (5/5710). AF 95% confidence interval is 0.000345. There are 0 homozygotes in GnomAdExome4. There are 7 alleles in the male GnomAdExome4 subpopulation. Median coverage is 31. This position passed quality control check.

BS2

High AC in GnomAd4 at 5 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000548.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TSC2	NM_000548.5	MANE Select	c.2545A>G	p.Thr849Ala	missense splice_region	Exon 22 of 42	NP_000539.2
TSC2	NM_001406663.1		c.2545A>G	p.Thr849Ala	missense splice_region	Exon 22 of 42	NP_001393592.1
TSC2	NM_001114382.3		c.2545A>G	p.Thr849Ala	missense splice_region	Exon 22 of 41	NP_001107854.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TSC2	ENST00000219476.9	TSL:5 MANE Select	c.2545A>G	p.Thr849Ala	missense splice_region	Exon 22 of 42	ENSP00000219476.3
TSC2	ENST00000350773.9	TSL:1	c.2545A>G	p.Thr849Ala	missense splice_region	Exon 22 of 41	ENSP00000344383.4
TSC2	ENST00000401874.7	TSL:1	c.2545A>G	p.Thr849Ala	missense splice_region	Exon 22 of 40	ENSP00000384468.2

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152190

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:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00949

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.000479

GnomAD2 exomes

AF:

0.0000121

AC:

AN:

247478

AF XY:

0.0000149

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000890

Gnomad OTH exome

AF:

0.000164

GnomAD4 exome

AF:

0.0000110

AC:

AN:

1457778

Hom.:

Cov.:

AF XY:

0.00000965

AC XY:

AN XY:

725304

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33470

American (AMR)

AF:

0.0000224

AC:

AN:

44712

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86250

European-Finnish (FIN)

AF:

0.00

AC:

AN:

49482

Middle Eastern (MID)

AF:

0.000876

AC:

AN:

5710

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1111982

Other (OTH)

AF:

0.0000994

AC:

AN:

60336

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.469

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000328

AC:

AN:

152308

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74464

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41564

American (AMR)

AF:

0.00

AC:

AN:

15306

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5184

South Asian (SAS)

AF:

0.000207

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00680

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68016

Other (OTH)

AF:

0.000474

AC:

AN:

2110

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.458

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000434

Hom.:

Bravo

AF:

0.0000189

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Tuberous sclerosis 2

Benign:3

Oct 14, 2024

Myriad Genetics, Inc.

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is considered likely benign. Homozygosity has been confirmed in one or more individuals. As homozygosity for pathogenic variants in this gene is generally assumed to result in embryonic lethality, this variant is unlikely to be pathogenic.

Jan 22, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Nov 07, 2021

Genome-Nilou Lab

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Tuberous sclerosis syndrome

Uncertain:1

Jun 28, 2023

All of Us Research Program, National Institutes of Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This missense variant replaces threonine with alanine at codon 849 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 tuberous sclerosis complex in the literature. This variant has been identified in 3/247478 chromosomes 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

Uncertain:1

Mar 02, 2022

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge

Hereditary cancer-predisposing syndrome

Uncertain:1

Dec 13, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.T849A variant (also known as c.2545A>G), located in coding exon 21 of the TSC2 gene, results from an A to G substitution at nucleotide position 2545. The threonine at codon 849 is replaced by alanine, an amino acid with similar properties. 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.

Lymphangiomyomatosis;C1846385:Isolated focal cortical dysplasia type II;C1860707:Tuberous sclerosis 2

Benign:1

May 20, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.21

BayesDel_addAF

Pathogenic

0.21

BayesDel_noAF

Pathogenic

0.15

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.75

Eigen

Uncertain

0.44

Eigen_PC

Uncertain

0.49

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.91

M_CAP

Uncertain

0.11

MetaRNN

Uncertain

0.74

MetaSVM

Uncertain

0.28

MutationAssessor

Benign

2.0

PhyloP100

7.2

PrimateAI

Uncertain

0.69

PROVEAN

Uncertain

-3.3

REVEL

Pathogenic

0.74

Sift

Benign

0.14

Sift4G

Uncertain

0.050

Polyphen

0.99

Vest4

0.72

MutPred

0.60

Loss of catalytic residue at T849 (P = 0.0771)

MVP

0.86

ClinPred

0.80

GERP RS

5.4

Varity_R

0.38

gMVP

0.65

Mutation Taster

=46/54

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.64

dbscSNV1_RF

Benign

0.41

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over