NM_001276345.2:c.430C>G

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM1PM2PM5PP3_ModeratePP5_Very_Strong

The NM_001276345.2(TNNT2):​c.430C>G​(p.Arg144Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R144P) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 33)

Consequence

TNNT2
NM_001276345.2 missense

Scores

10
3
4

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5

Conservation

PhyloP100: 0.276

Publications

25 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

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ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 16 ACMG points.

PM1
In a hotspot region, there are 13 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 21 uncertain in NM_001276345.2
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr1-201364356-C-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 982844.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.89
PP5
Variant 1-201364357-G-C is Pathogenic according to our data. Variant chr1-201364357-G-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 43639.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TNNT2NM_001276345.2 linkc.430C>G p.Arg144Gly missense_variant Exon 11 of 17 ENST00000656932.1 NP_001263274.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TNNT2ENST00000656932.1 linkc.430C>G p.Arg144Gly missense_variant Exon 11 of 17 NM_001276345.2 ENSP00000499593.1

Frequencies

GnomAD3 genomes
Cov.:
33
GnomAD4 exome
Cov.:
31
GnomAD4 genome
Cov.:
33

ClinVar

Significance: Pathogenic/Likely pathogenic
Submissions summary: Pathogenic:5
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Dilated cardiomyopathy 1D Pathogenic:1
Apr 11, 2023
Genome-Nilou Lab
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Cardiomyopathy, familial restrictive, 3 Pathogenic:1
Apr 11, 2023
Genome-Nilou Lab
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Primary dilated cardiomyopathy Pathogenic:1
Feb 21, 2014
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The Arg134Gly variant in TNNT2 has been reported in 1 individual with DCM, was a bsent from 506 control chromosomes, and segregated with disease in 4 affected re latives from 1 family (Hershberger 2008, Hershberger 2009). Data from large popu lation studies is insufficient to assess the frequency of this variant. This var iant has also been identified by our laboratory in 1 Caucasian individual with D CM (this family) and segregated with disease in 3 affected relatives, but was no t detected in 1 other affected relative (more distantly related). Arginine (Arg) at position 134 is conserved in evolution and the change to glycine (Gly) was p redicted to be pathogenic using a computational tool clinically validated by our laboratory. This tool's pathogenic prediction is estimated to be correct 94% of the time (Jordan 2011). In summary, this variant is likely pathogenic, though a dditional studies are required to fully establish its clinical significance.

Hypertrophic cardiomyopathy 2 Pathogenic:1
Apr 11, 2023
Genome-Nilou Lab
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Dilated cardiomyopathy 1D;C1861864:Hypertrophic cardiomyopathy 2;C2676271:Cardiomyopathy, familial restrictive, 3 Pathogenic:1
Apr 17, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

For these reasons, this variant has been classified as Pathogenic. Experimental studies have shown that this missense change affects TNNT2 function (PMID: 20031601, 34161147). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. ClinVar contains an entry for this variant (Variation ID: 43639). This missense change has been observed in individuals with dilated cardiomyopathy (PMID: 20031601, 33025817). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 134 of the TNNT2 protein (p.Arg134Gly).

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.97
CardioboostCm
Pathogenic
1.0
BayesDel_addAF
Pathogenic
0.44
D
BayesDel_noAF
Pathogenic
0.40
CADD
Uncertain
25
DANN
Uncertain
1.0
DEOGEN2
Benign
0.0
.;.;.;.;D;.;.;.;.;.;D;.
Eigen
Uncertain
0.38
Eigen_PC
Benign
0.20
LIST_S2
Benign
0.0
.;D;D;D;D;D;D;.;.;D;.;.
M_CAP
Pathogenic
0.95
D
MetaRNN
Pathogenic
0.89
D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM
Pathogenic
1.1
D
MutationAssessor
Benign
0.0
.;.;.;.;M;.;.;.;.;.;.;.
PhyloP100
0.28
PrimateAI
Uncertain
0.70
T
PROVEAN
Pathogenic
-6.2
D;D;D;.;D;.;.;.;D;D;D;D
Sift
Pathogenic
0.0
D;D;D;.;D;.;.;.;D;D;D;D
Sift4G
Pathogenic
0.0010
D;D;D;D;D;D;D;D;D;D;.;D
Vest4
0.89
ClinPred
1.0
D
GERP RS
3.3
Varity_R
0.86
gMVP
1.0
Mutation Taster
=0/100
disease causing (ClinVar)

Splicing

Name
Calibrated prediction
Score
Prediction
Splicevardb
2.0
SpliceAI score (max)
0.010
Details are displayed if max score is > 0.2

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

Publications

Other links and lift over

dbSNP: rs45525839; hg19: chr1-201333485; API