NM_001276345.2:c.260C>T

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1PM5PP3_Moderate

The NM_001276345.2(TNNT2):c.260C>T(p.Pro87Leu) variant causes a missense change. The variant allele was found at a frequency of 0.0000204 in 1,613,898 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. P87T) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000021 ( 0 hom. )

Consequence

TNNT2
NM_001276345.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:14

Conservation

PhyloP100: 6.85

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: Likely_pathogenic. The variant received 6 ACMG points.

PM1

In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 14 uncertain in NM_001276345.2

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-201365645-G-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 181610.We mark this variant Likely_pathogenic, oryginal submission is: [Conflicting_classifications_of_pathogenicity].

PP3

MetaRNN computational evidence supports a deleterious effect, 0.882

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TNNT2	NM_001276345.2 link	c.260C>T	p.Pro87Leu	missense_variant	Exon 9 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.260C>T	p.Pro87Leu	missense_variant	Exon 9 of 17		NM_001276345.2	ENSP00000499593.1		P45379-1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152136

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

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:

0.000478

GnomAD2 exomes

AF:

0.0000398

AC:

AN:

251110

AF XY:

0.0000368

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000174

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000205

AC:

AN:

1461762

Hom.:

Cov.:

AF XY:

0.0000179

AC XY:

AN XY:

727148

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.000134

AC:

AN:

44708

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86206

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000189

AC:

AN:

1111960

Other (OTH)

AF:

0.0000497

AC:

AN:

60392

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.442

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152136

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74302

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41434

American (AMR)

AF:

0.000131

AC:

AN:

15270

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4812

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10614

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68020

Other (OTH)

AF:

0.000478

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.508

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000360

Hom.:

Bravo

AF:

0.0000416

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000412

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:14

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:3

Clinical Genetics, Academic Medical Center

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Apr 25, 2025

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Identified in an individual with apical hypertrophy and LVNC; the variant segregated with disease in an affected child (PMID: 20530761); Reported in an individual with sudden cardiac death in adulthood (PMID: 11560853); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 23299917, 19914256, 34426522, 33025817, 25637381, 11560853, 20530761) -

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Cardiomyopathy

Uncertain:2

Nov 18, 2024

Color Diagnostics, LLC DBA Color Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This missense variant replaces proline with leucine at codon 77 of the TNNT2 protein. Computational prediction tool is inconclusive regarding the impact of this variant on protein structure and function. An in vitro functional study using a reporter assay system has shown that this variant does not significantly alter TNNT2 activity (PMID: 33025817). This variant has been reported in an individual affected with hypertrophic cardiomyopathy with sudden cardiac death (PMID: 11560853), in an individual affected with left ventricular noncompaction (PMID: 20530761, 29447731, 33500567), and in individuals affected with dilated cardiomyopathy (PMID: 37904629, 38612618). This variant has been identified in 10/251110 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. -

Feb 05, 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 proline with leucine at codon 77 of the TNNT2 protein. Computational prediction suggests that this variant may have a 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 been reported in an individual affected with hypertrophic cardiomyopathy and sudden cardiac death (PMID: 11560853) and in an individual affected with left ventricular noncompaction cardiomyopathy (PMID: 20530761). This variant has been identified in 10/251110 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. -

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

Uncertain:2

Sep 08, 2021

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 22, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 77 of the TNNT2 protein (p.Pro77Leu). This variant is present in population databases (rs144900708, gnomAD 0.02%). This missense change has been observed in individual(s) with peripartum cardiomyopathy and dilated cardiomyopathy and/or TNNT2-related conditions (PMID: 11560853, 20530761; internal data). This variant is also known as p.Pro87Leu. ClinVar contains an entry for this variant (Variation ID: 43619). 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 TNNT2 protein function with a negative predictive value of 80%. 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. -

not specified

Uncertain:1

Oct 03, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The Pro77Leu variant in TNNT2 has been identified in 1 individual with HCM/SCD ( Varnava 2001) as well as in 1/8600 European American chromosomes from a broad po pulation by the NHLBI Exome Sequencing Project (http://evs.gs.washington.edu/EVS /; dbSNP rs144900708). Proline (Pro) at position 77 is conserved in mammals and some evolutionarily distant species, but frog and stickleback carry a leucine (L eu; this variant) at this position suggesting that this change may be tolerated. Other computational analyses (biochemical amino acid properties, AlignGVGD, Pol yPhen2, and SIFT) suggest that this variant may not impact the protein, though t his information is not predictive enough to rule out pathogenicity. Additional s tudies are needed to fully assess the clinical significance of this variant. -

Dilated cardiomyopathy 1D

Uncertain:1

Apr 11, 2023

Genome-Nilou Lab

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

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

- -

Primary familial hypertrophic cardiomyopathy

Uncertain:1

Jun 01, 2014

CSER _CC_NCGL, University of Washington

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:research

- -

Cardiovascular phenotype

Uncertain:1

Dec 07, 2021

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.230C>T (p.P77L) alteration is located in exon 8 (coding exon 7) of the TNNT2 gene. This alteration results from a C to T substitution at nucleotide position 230, causing the proline (P) at amino acid position 77 to be replaced by a leucine (L). Based on insufficient or conflicting evidence, the clinical significance of this alteration 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

- -

TNNT2-related disorder

Uncertain:1

Jul 26, 2024

PreventionGenetics, part of Exact Sciences

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

The TNNT2 c.230C>T variant is predicted to result in the amino acid substitution p.Pro77Leu. This variant has been reported in an individual diagnosed with hypertrophic cardiomyopathy after sudden cardiac death (Varnava et al. 2001. PubMed ID: 11560853). This variant, also described as p.Pro87Leu, has also been reported in two members of a family with left ventricular noncompaction cardiomyopathy (Hoedemaekers et al. 2010. PubMed ID: 20530761). An in vitro reporter assay did not demonstrate a significant difference between this variant and wildtype (Figure 4G, Pettinato et al. 2020. PubMed ID: 33025817). This variant is reported in 0.017% of alleles in individuals of Latino descent in gnomAD, and has been consistently interpreted as uncertain by several laboratories in the ClinVar database (https://www.ncbi.nlm.nih.gov/clinvar/variation/43619/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.73

CardioboostCm

Pathogenic

0.93

BayesDel_addAF

Pathogenic

0.33

BayesDel_noAF

Pathogenic

0.51

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

DEOGEN2

Pathogenic

0.92

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

Eigen

Uncertain

0.24

Eigen_PC

Uncertain

0.34

FATHMM_MKL

Uncertain

0.97

LIST_S2

Uncertain

0.97

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

M_CAP

Pathogenic

0.79

MetaRNN

Pathogenic

0.88

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

MetaSVM

Pathogenic

1.0

MutationAssessor

Uncertain

2.9

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

PhyloP100

6.9

PrimateAI

Pathogenic

0.82

PROVEAN

Pathogenic

-8.2

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

REVEL

Pathogenic

0.70

Sift

Uncertain

0.028

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

Sift4G

Uncertain

0.041

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

Polyphen

0.57, 0.090

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

Vest4

0.55

MVP

0.97

MPC

1.4

ClinPred

0.87

GERP RS

4.7

Varity_R

0.20

gMVP

0.96

Mutation Taster

=0/100

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

Splicevardb

2.0

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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NM_001276345.2:c.260C>T

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over