rs45525839
Variant summary
Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM1PM5PP3_ModeratePP5
The NM_001276345.2(TNNT2):c.430C>T(p.Arg144Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000682 in 1,612,824 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R144P) has been classified as Likely pathogenic.
Frequency
Consequence
NM_001276345.2 missense
Scores
Clinical Significance
Conservation
Publications
- dilated cardiomyopathyInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- dilated cardiomyopathy 1DInheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
- hypertrophic cardiomyopathyInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- hypertrophic cardiomyopathy 2Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
- hypertrophic cardiomyopathy 3Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
- cardiomyopathy, familial restrictive, 3Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
- familial isolated dilated cardiomyopathyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- familial isolated restrictive cardiomyopathyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- left ventricular noncompactionInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- cardiomyopathyInheritance: AR Classification: LIMITED Submitted by: Ambry Genetics
- arrhythmogenic right ventricular cardiomyopathyInheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
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ACMG classification
Our verdict: Likely_pathogenic. The variant received 7 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152202Hom.: 0 Cov.: 33 show subpopulations
GnomAD2 exomes AF: 0.00000400 AC: 1AN: 249858 AF XY: 0.00000739 show subpopulations
GnomAD4 exome AF: 0.00000616 AC: 9AN: 1460622Hom.: 0 Cov.: 31 AF XY: 0.00000826 AC XY: 6AN XY: 726656 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152202Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0AN XY: 74358 show subpopulations
ClinVar
Submissions by phenotype
not provided Pathogenic:1Uncertain:1
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Reported in association with cardiomyopathy in unrelated patients in published literature and referred for genetic testing at GeneDx (PMID: 27532257, 34853230, 33297573, 38473809); Not observed at significant frequency in large population cohorts (gnomAD); 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: 30565988, 23861362, 33297573, 34853230, 27532257, 38473809, 37652022, 20031601) -
Cardiomyopathy Uncertain:2
This missense variant replaces arginine with tryptophan at codon 134 in the tropomyosin binding domain 1 of the TNNT2 protein. Computational prediction tools indicate that this variant has a deleterious impact on protein structure and function. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in two individuals affected with hypertrophic cardiomyopathy (PMID: 27532257, 33297573), in one individual affected with left ventricular noncompaction (PMID: 34853230), and in one individual affected with dilated cardiomyopathy (PMID: 38473809). This variant has been identified in 1/249858 chromosomes in the general population by the Genome Aggregation Database (gnomAD). A different variant affecting the same codon, p.Arg134Gly, is considered to be disease-causing (ClinVar variation ID: 43639), suggesting that arginine at this position is important for TNNT2 protein function. Although there is a suspicion that this variant may be associated with disease, additional studies are necessary to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
This missense variant replaces arginine with tryptophan at codon 134 in the tropomyosin binding domain 1 of the TNNT2 protein. Computational prediction tools indicate that this variant has a deleterious impact on protein structure and function. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in two individuals affected with hypertrophic cardiomyopathy (PMID: 27532257, 33297573), in one individual affected with left ventricular noncompaction (PMID: 34853230), and in one individual affected with dilated cardiomyopathy (PMID: 38473809). This variant has been identified in 1/249858 chromosomes in the general population by the Genome Aggregation Database (gnomAD). A different variant affecting the same codon, p.Arg134Gly, is considered to be disease-causing (ClinVar variation ID: 43639), suggesting that arginine at this position is important for TNNT2 protein function. Although there is a suspicion that this variant may be associated with disease, additional studies are necessary to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Dilated cardiomyopathy 1D Pathogenic:1
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Dilated cardiomyopathy 1D;C1861864:Hypertrophic cardiomyopathy 2 Pathogenic:1
The c.430C>T (p.Arg144Trp) variant identified in TNNT2 has been reported in the literature in at least two individuals affected with hypertrophic cardiomyopathy [PMID: 27532257, 33297573], and has been deposited in ClinVar as a Variant of Uncertain Significance [ClinVar ID:127070]. The c.430C>T variant is observed in 3 out of 588,858 heterozygous alleles (no homozygotes) in population databases (gnomAD v2.1.1 and v3.1.2, TOPMed Freeze 8) which might include individuals with cardiac abnormalities. The variant is located in exon 10 of this 16-exon gene, and is predicted to replace an evolutionarily conserved arginine aminoacid with tryptophan at position 144 in the Troponin domain of the encoded protein [uniport ID: P45379]. In silico predictions are in favor of damaging effect forp.(Arg144Trp) [REVEL score = 0.796]. An in vitro functional study showed that the induced pluripotent stem cell-differentiated cardiomyocytes (iPSC-CMs) carrying thec.430C>T p.(Arg144Trp) variant had an impaired response to isoproterenol when compared to the control iPSC-CMs [PMID: 30565988]. Based on available evidence, this c.430C>T p.(Arg144Trp) variant identified in TNNT2 is classified as Likely Pathogenic. -
Dilated cardiomyopathy 1D;C1861864:Hypertrophic cardiomyopathy 2;C2676271:Cardiomyopathy, familial restrictive, 3 Pathogenic:1
This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 134 of the TNNT2 protein (p.Arg134Trp). 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 individuals with dilated cardiomyopathy and/or hypertrophic cardiomyopathy (PMID: 27532257, 33297573, 37652022; internal data). This variant is also known as R144W. ClinVar contains an entry for this variant (Variation ID: 127070). 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 expected to disrupt TNNT2 protein function with a positive predictive value of 80%. Experimental studies have shown that this missense change affects TNNT2 function (PMID: 30565988). This variant disrupts the p.Arg134 amino acid residue in TNNT2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 20031601, 22464770). 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. -
not specified Uncertain:1
Variant summary: TNNT2 c.400C>T (p.Arg134Trp) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 249858 control chromosomes (gnomAD). c.400C>T has been reported in the literature in individuals affected with HCM, DCM or LVNC (Walsh_2017, Micheu_2020, Miyake_2021, McGurk_2023, Kurzlechner_2022). These data do not allow any conclusion about variant significance. At least one publication reports experimental evidence evaluating an impact on protein function and this variant disrupts protein function (Lv_2018). The following publications have been ascertained in the context of this evaluation (PMID: 35629155, 30565988, 37652022, 33297573, 34853230, 27532257). ClinVar contains an entry for this variant (Variation ID: 127070). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -
Primary dilated cardiomyopathy Uncertain:1
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Cardiovascular phenotype Uncertain:1
The p.R134W variant (also known as c.400C>T), located in coding exon 9 of the TNNT2 gene, results from a C to T substitution at nucleotide position 400. The arginine at codon 134 is replaced by tryptophan, an amino acid with dissimilar properties. This variant has been detected in two individuals from hypertrophic cardiomyopathy (HCM) cohorts; however, clinical details were limited (Walsh R et al. Genet Med, 2017 02;19:192-203; Micheu MM et al. Diagnostics (Basel), 2020 Dec;10). The variant (referred to as p.R144W c.430C>T) co-occurred with an MYH7 variant in an individual with findings of left ventricular non-compaction findings (Miyake W et al. Int Heart J, 2021;62:1420-1429). This alteration has also been reported as a secondary cardiac variant in an exome cohort (Ng D et al. Circ Cardiovasc Genet, 2013 Aug;6:337-46). 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. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at