NM_001276345.2:c.863G>A

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.863G>A(p.Arg288His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000149 in 1,611,322 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R288P) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.000053 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000011 ( 0 hom. )

Consequence

TNNT2
NM_001276345.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:13

Conservation

PhyloP100: 1.79

Publications

19 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 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 21 uncertain in NM_001276345.2

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-201359244-C-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 177635.

BP4

Computational evidence support a benign effect (MetaRNN=0.20222434).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001276345.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TNNT2	NM_001276345.2	MANE Select	c.863G>A	p.Arg288His	missense	Exon 17 of 17	NP_001263274.1
TNNT2	NM_000364.4		c.854G>A	p.Arg285His	missense	Exon 16 of 16	NP_000355.2
TNNT2	NM_001406723.1		c.854G>A	p.Arg285His	missense	Exon 16 of 16	NP_001393652.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TNNT2	ENST00000656932.1	MANE Select	c.863G>A	p.Arg288His	missense	Exon 17 of 17	ENSP00000499593.1
TNNT2	ENST00000367322.6	TSL:1	c.821G>A	p.Arg274His	missense	Exon 15 of 15	ENSP00000356291.2
TNNT2	ENST00000367320.6	TSL:1	c.734G>A	p.Arg245His	missense	Exon 15 of 15	ENSP00000356289.2

Frequencies

GnomAD3 genomes

AF:

0.0000526

AC:

AN:

152136

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000966

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000123

AC:

AN:

244400

AF XY:

0.0000228

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:

0.00000906

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000110

AC:

AN:

1459068

Hom.:

Cov.:

AF XY:

0.0000152

AC XY:

AN XY:

725326

show subpopulations

African (AFR)

AF:

0.0000598

AC:

AN:

33460

American (AMR)

AF:

0.00

AC:

AN:

44406

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26038

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39654

South Asian (SAS)

AF:

0.0000941

AC:

AN:

85054

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53238

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5704

European-Non Finnish (NFE)

AF:

0.00000450

AC:

AN:

1111220

Other (OTH)

AF:

0.00

AC:

AN:

60294

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.478

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:

0.0000525

AC:

AN:

152254

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74436

show subpopulations

African (AFR)

AF:

0.0000963

AC:

AN:

41544

American (AMR)

AF:

0.00

AC:

AN:

15304

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000193

AC:

AN:

5174

South Asian (SAS)

AF:

0.000207

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10604

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68016

Other (OTH)

AF:

0.00

AC:

AN:

2112

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.519

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:

0.0000905

Hom.:

Bravo

AF:

0.0000264

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:13

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Cardiomyopathy

Uncertain:3

May 28, 2021

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Feb 22, 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 arginine with histidine at codon 278 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 seven unrelated individuals affected with hypertrophic cardiomyopathy (PMID: 22144547, 27532257, 28408708, 28771489, 28790153, 28971120 , 28971120, 33297573). This variant has also been reported in a family affected with hypertrophic cardiomyopathy including two affected carriers and one unaffected carrier (PMID: 34087240). This variant has been identified in 4/275756 chromosomes in the general population by the Genome Aggregation Database (gnomAD). A different variant affecting the same codon, p.Arg278Pro, is considered to be disease-causing (ClinVar variation ID: 177635), suggesting that arginine at this position is important for TNNT2 protein function. 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.

Aug 27, 2024

Color Diagnostics, LLC DBA Color Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This missense variant replaces arginine with histidine at codon 278 of the TNNT2 protein. Computational prediction tools indicate that this variant has a neutral impact on protein structure and function. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in seven unrelated individuals affected with hypertrophic cardiomyopathy (PMID: 22144547, 27532257, 28408708, 28771489, 28790153, 28971120 , 28971120, 33297573, 34087240). In one family affected with hypertrophic cardiomyopathy, this variant has been reported in two affected carriers and one unaffected carrier (PMID: 34087240). This variant has been identified in 4/275756 chromosomes in the general population by the Genome Aggregation Database (gnomAD). A different variant affecting the same codon, p.Arg278Pro, is considered to be disease-causing (ClinVar variation ID: 177635), suggesting that arginine at this position is important for TNNT2 protein function. 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:3

Clinical Genetics, Academic Medical Center

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

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

Jul 12, 2022

Mayo Clinic Laboratories, Mayo Clinic

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

PM5, PS4_moderate

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

Pathogenic:1Uncertain:1

Dec 04, 2021

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Nov 26, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 278 of the TNNT2 protein (p.Arg278His). This variant is present in population databases (rs397516484, gnomAD 0.01%). This missense change has been observed in individual(s) with hypertrophic cardiomyopathy (PMID: 20624503, 22144547, 27532257, 28408708, 33297573). This variant is also known as p.Arg288His. ClinVar contains an entry for this variant (Variation ID: 43674). 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%. This variant disrupts the p.Arg278 amino acid residue in TNNT2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 12974739, 15958377, 23283745, 24793961). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic.

Hypertrophic cardiomyopathy

Uncertain:2

Nov 26, 2019

Agnes Ginges Centre for Molecular Cardiology, Centenary Institute

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:research

This TNNT2 Arg278His variant has been reported in 3 HCM probands (Pasquale F, et al., 2012; Walsh R et al., 2017). This variant is present in the Genome Aggregation Database (http://gnomad.broadinstitute.org/). We have identified TNNT2 Arg278His in a proband with HCM, but no family history of disease or sudden cardiac death (Ingles et al., 2017). The proband also carries 2 other variants (TNNT2 c.571-7G>A & MYH7 c.1000-7C>T). Interestingly, different rare variants at this position (Arg278Cys and Arg278Pro) have also been reported in multiple HCM individuals, suggesting that an amino acid substitution at this site may not be tolerated. Computational tools SIFT, MutationTaster, and PolyPhen-2 predict this variant to have a deleterious effect. Based on the adapted ACMG guidelines (Kelly MA, et al., 2018), the variant is rare in the general population (PM2), has been identified in 4 HCM probands and in silico tools predict the variant to be deleterious, therefore we classify TNNT2 Arg278His as a variant of "uncertain significance".

Apr 04, 2019

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Disclaimer: This variant has not undergone full assessment. The following are preliminary notes: This variant has been reported in two probands with HCM (Pasquale 2012, Burns 2017). Gnomad: 0.01% (3 alleles). Clinvar: VUS (Agnes Ginges). Three other variants at this position are reported in HGMD.

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

Hypertrophic cardiomyopathy 2

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

Apr 15, 2019

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.833G>A (p.R278H) alteration is located in exon 16 (coding exon 15) of the TNNT2 gene. This alteration results from a G to A substitution at nucleotide position 833, causing the arginine (R) at amino acid position 278 to be replaced by a histidine (H). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.52

CardioboostCm

Uncertain

0.62

BayesDel_addAF

Uncertain

0.013

BayesDel_noAF

Uncertain

-0.010

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.60

Eigen

Uncertain

0.28

Eigen_PC

Uncertain

0.27

FATHMM_MKL

Benign

0.66

LIST_S2

Uncertain

0.93

M_CAP

Pathogenic

0.34

MetaRNN

Benign

0.20

MetaSVM

Uncertain

-0.045

MutationAssessor

Benign

1.2

PhyloP100

1.8

PrimateAI

Uncertain

0.59

PROVEAN

Benign

-1.3

REVEL

Uncertain

0.42

Sift

Benign

0.18

Sift4G

Benign

0.21

Polyphen

1.0

Vest4

0.48

MVP

0.93

MPC

1.6

ClinPred

0.73

GERP RS

4.0

Varity_R

0.098

gMVP

0.40

Mutation Taster

=0/100

disease causing

(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

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