1-201359639-T-C

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 4P and 2B. PM1PM5BP4_Moderate

The NM_001276345.2(TNNT2):c.835A>G(p.Asn279Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000813 in 1,598,080 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts 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. N279S) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000076 ( 0 hom. )

Consequence

TNNT2
NM_001276345.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:9

Conservation

PhyloP100: 3.29

Publications

4 publications found

Variant links:

Genes affected

TNNT2 (HGNC:11949): (troponin T2, cardiac type) This gene encodes the cardiac isoform of troponin T. The encoded protein is the tropomyosin-binding subunit of the troponin complex, which is located on the thin filament of striated muscles and regulates muscle contraction in response to alterations in intracellular calcium ion concentration. Mutations in this gene have been associated with familial hypertrophic cardiomyopathy as well as with dilated cardiomyopathy. [provided by RefSeq, May 2022]

TNNT2 Gene-Disease associations (from GenCC):

dilated cardiomyopathy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
dilated cardiomyopathy 1D
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
hypertrophic cardiomyopathy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
hypertrophic cardiomyopathy 2
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
hypertrophic cardiomyopathy 3
Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
cardiomyopathy, familial restrictive, 3
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
familial isolated dilated cardiomyopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
familial isolated restrictive cardiomyopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
left ventricular noncompaction
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
cardiomyopathy
Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics
arrhythmogenic right ventricular cardiomyopathy
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

TNNT2 links:

ENSG00000286600 (HGNC:):

ENSG00000286600 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 0 benign, 17 uncertain in NM_001276345.2

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-201359637-G-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 177855.Status of the report is criteria_provided_single_submitter, 1 stars.

BP4

Computational evidence support a benign effect (MetaRNN=0.23671263).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TNNT2	NM_001276345.2 link	c.835A>G	p.Asn279Asp	missense_variant	Exon 16 of 17	ENST00000656932.1	NP_001263274.1	P45379-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TNNT2	ENST00000656932.1 link	c.835A>G	p.Asn279Asp	missense_variant	Exon 16 of 17		NM_001276345.2	ENSP00000499593.1		P45379-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152152

Hom.:

Cov.:

show subpopulations

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000443

AC:

AN:

225746

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000101

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000761

AC:

AN:

1445928

Hom.:

Cov.:

AF XY:

0.00000557

AC XY:

AN XY:

717534

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33158

American (AMR)

AF:

0.00

AC:

AN:

43178

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25832

East Asian (EAS)

AF:

0.00

AC:

AN:

39270

South Asian (SAS)

AF:

0.00

AC:

AN:

83756

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52394

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5754

European-Non Finnish (NFE)

AF:

0.00000907

AC:

AN:

1102804

Other (OTH)

AF:

0.0000167

AC:

AN:

59782

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.461

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:

0.0000131

AC:

AN:

152152

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74312

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41422

American (AMR)

AF:

0.00

AC:

AN:

15286

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68018

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000386

Hom.:

Bravo

AF:

0.0000151

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:9

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Cardiomyopathy

Uncertain:3

Mar 24, 2024

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 asparagine with aspartic acid at codon 269 of the TNNT2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with hypertrophic cardiomyopathy (PMID: 27532257, 33495597). This variant has been identified in 1/225746 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. -

Apr 28, 2016

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jun 01, 2023

Color Diagnostics, LLC DBA Color Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Dilated cardiomyopathy 1D

Uncertain:1

Apr 11, 2023

Genome-Nilou Lab

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Uncertain:1

Jun 12, 2017

Stanford Center for Inherited Cardiovascular Disease, Stanford University

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:provider interpretation

p.Asn269Asp (c.805A>G; chr1:201328767) in the TNNT2 gene (NM_001001430.2) Given the lack of case data, we consider this variant a variant of uncertain significance and we do not feel it is suitable for assessing risk in healthy relatives ("predictive genetic testing"). To our knowledge, there is no published literature that associates this variant with cardiomyopathy. This variant is present in ClinVar, but has only been submitted by Invitae. Per the test report, "Algorithms developed to predict the e ect of missense changes on protein structure and function (SIFT, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have notcon rmed by published functional studies." The asparagine at codon 269 is moderately conserved across species, as are neighboring amino acids. Another variant at this codon, p.Asn269Ser, is classified as a variant of uncertain significance by 2 labs in ClinVar. A variant at a nearby codon is currently classified as a pathogenic variant by GeneDx; however, it was last reviewed in 2011 and by the ACMG's 2015 criteria, would be called a variant of uncertain significance. The variant was reported online in 2 of 110,230 individuals in the Genome Aggregation Consortium Dataset (gnomAD; http://gnomad.broadinstitute.org/), which currently includes variant calls on >140,000 unrelated individuals of African, Asian, European, Ashkenazi, Latino descent. Specifically, the variant was observed in 2 of 46,523 individuals of European descent (MAF=0.002%). The phenotype of those individuals is not publicly available. The dataset is comprised of multiple cohorts, some of which were recruited from the general population, others were enriched for common cardiovascular disease. Note that other variants with strong evidence for pathogenicity have been seen at similar frequencies in datasets like this so this does not necessarily rule out pathogenicity (Pan et al 2012). Another variant at this codon is present at relatively high frequency in gnomAD; however, it is a synonymous variant (p.Asn269Asn; MAF=0.01%). -

Cardiomyopathy, familial restrictive, 3

Uncertain:1

Apr 11, 2023

Genome-Nilou Lab

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Cardiovascular phenotype

Uncertain:1

Jul 31, 2024

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.N269D variant (also known as c.805A>G), located in coding exon 14 of the TNNT2 gene, results from an A to G substitution at nucleotide position 805. The asparagine at codon 269 is replaced by aspartic acid, an amino acid with highly similar properties. This alteration has been reported in individuals with hypertrophy cardiomyopathy (HCM) (Walsh R et al. Genet Med, 2017 Feb;19:192-203; Ho CY et al. Circulation, 2018 Oct;138:1387-1398l; Ambry internal data). This amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -

Hypertrophic cardiomyopathy 2

Uncertain:1

Apr 11, 2023

Genome-Nilou Lab

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Dilated cardiomyopathy 1D;C1861864:Hypertrophic cardiomyopathy 2;C2676271:Cardiomyopathy, familial restrictive, 3

Uncertain:1

Feb 23, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces asparagine, which is neutral and polar, with aspartic acid, which is acidic and polar, at codon 269 of the TNNT2 protein (p.Asn269Asp). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This missense change has been observed in individual(s) with hypertrophic cardiomyopathy (PMID: 27532257). ClinVar contains an entry for this variant (Variation ID: 181647). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on TNNT2 protein function. Experimental studies have shown that this missense change does not substantially affect TNNT2 function (PMID: 33025817). 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.74

CardioboostCm

Uncertain

0.11

BayesDel_addAF

Benign

-0.11

BayesDel_noAF

Benign

-0.40

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.54

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

Eigen

Benign

-0.20

Eigen_PC

Benign

-0.066

FATHMM_MKL

Uncertain

0.92

LIST_S2

Benign

0.85

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

M_CAP

Uncertain

0.15

MetaRNN

Benign

0.24

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

MetaSVM

Benign

-0.55

MutationAssessor

Benign

-0.14

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

PhyloP100

3.3

PrimateAI

Uncertain

0.73

PROVEAN

Benign

-0.52

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

REVEL

Benign

0.20

Sift

Benign

0.60

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

Sift4G

Benign

0.53

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

Polyphen

0.073

.;.;.;.;B;.;.;.;.;.;.

Vest4

0.34

MVP

0.82

MPC

0.59

ClinPred

0.38

GERP RS

4.1

Varity_R

0.72

gMVP

0.65

Mutation Taster

=77/23

polymorphism

(source)

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

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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