rs74315379

Positions:

• chr1-201364336-G-A
• chr1-201364336-G-T

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PM5 PP3_Moderate PP5_Very_Strong

The NM_001276345.2(TNNT2):​c.451C>T​(p.Arg151Trp) variant causes a missense change. 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 Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R151Q) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TNNT2 NM_001276345.2 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:18
• Conservation: PhyloP100: 5.39

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]

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PM1: In a region_of_interest Disordered (size 99) in uniprot entity TNNT2_HUMAN there are 38 pathogenic changes around while only 2 benign (95%) 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 chr1-201364335-C-T is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.916
• PP5: Variant 1-201364336-G-A is Pathogenic according to our data. Variant chr1-201364336-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 12414.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-201364336-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TNNT2	NM_001276345.2	c.451C>T	p.Arg151Trp	missense_variant	11/17	ENST00000656932.1	NP_001263274.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TNNT2	ENST00000656932.1	c.451C>T	p.Arg151Trp	missense_variant	11/17		NM_001276345.2	ENSP00000499593	A2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1460682 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726660

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:18

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Dilated cardiomyopathy 1D Pathogenic:5

Pathogenic, no assertion criteria provided	literature only	OMIM	Oct 30, 2001	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Apr 11, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Neuberg Centre For Genomic Medicine, NCGM	-	The missense variant c.451C>T (p.Arg151Trp) in TNNT2 gene has been reported in individuals and families affected with dilated cardiomyopathy (Li D et.al.,2001). This variant has been reported to the ClinVar database as Pathogenic .The p.Arg151Trp variant is novel (not in any individuals) in gnomAD Exomes and 1000 Genomes. The amino acid Arg at position 151 is changed to a Trp changing protein sequence and it might alter its composition and physico-chemical properties. The variant is predicted to be damaging by both SIFT and PolyPhen2. The residue is conserved across species. The amino acid change p.Arg151Trp in TNNT2 is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. For these reasons, this variant has been classified as Pathogenic . -
Pathogenic, criteria provided, single submitter	clinical testing	Victorian Clinical Genetics Services, Murdoch Childrens Research Institute	Dec 21, 2023	Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0105 - The mechanism of disease for this gene is not clearly established. Functional studies have suggested loss-of-function, gain-of-function and dominant-negative mechanisms based on calcium sensitivity, contractibility and mouse models (PMID: 18612386, 32098556, 33025817). (I) 0107 - This gene is associated with autosomal dominant disease. (I) 0115 - Variants in this gene are known to have variable expressivity. Some variants have been reported to cause both DCM and HCM, even within the same family (PMID: 26507537). (I) 0200 - Variant is predicted to result in a missense amino acid change from arginine to tryptophan. (I) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0309 - An alternative amino acid change at the same position has been observed in gnomAD (v2) (2 heterozygotes, 0 homozygotes). (I) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0600 - Variant is located in the annotated troponin domain (NCBI). (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. The variant has previously been reported as pathogenic in multiple patients with TNNT2-related cardiomyopathies including many with DCM, and is often annotated as p.(R141W) using an alternative transcript. It has been reported as de novo in some individuals, and has also been observed to segregate with the disease in families (ClinVar, PMID: 26656454). (SP) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
Pathogenic, criteria provided, single submitter	clinical testing	Center for Medical Genetics Ghent, University of Ghent	Jan 01, 2016	- -

not provided Pathogenic:4

Pathogenic, no assertion criteria provided	clinical testing	Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Dec 12, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jan 23, 2023	Affects cardiac muscle contractile dynamics by decreasing Ca2+ sensitivity of activation, reducing affinity of Ca2+ binding in the troponin complex, and/or increasing the rate of Ca2+ dissociation from the thin filament (Lu et al., 2003; Mirza et al., 2005; Venkatraman et al., 2005; Robinson et al., 2007; Liu et al., 2012; Sommese et al., 2013; Memo et al., 2013; Gollapudi et al., 2015); 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: 24367593, 28166811, 24992688, 25611685, 33336002, 34935411, 25681424, 23539503, 17932326, 12923187, 15623536, 11684629, 15923195, 22675533, 21846512, 15769782, 27936050, 27532257, 24503780, 21310275, 26656454, no PMID, 33025817, 34540771, 33906374, 32746448, 32758068, 34076677, 35288587, 14654368, 18606313) -
Pathogenic, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -

Cardiomyopathy Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario	Jun 23, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Apr 15, 2021	Variant summary: TNNT2 c.421C>T (p.Arg141Trp) 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 was absent in 250316 control chromosomes. c.421C>T has been reported in the literature in multiple individuals affected with Cardiomyopathy (e.g. Li_2001, Millart_2011, Alfares_2015, Long_2015, Walsh_2016). These data indicate that the variant is very likely to be associated with disease. In a large multi-generational family study, the variant was detected in at least 14 affected family members, although several unaffected individuals also carried the variant, suggesting incomplete penetrance (e.g. Li_2001). The variant has also been reported as a de-novo mutation in an individual with sporadic disease (e.g. Long_2015). Multiple publications report in-vitro or in-vivo experimental evidence that the variant results in calcium desensitization in cardiac muscle fibers (e.g. Lu_2003, Mirza_2005, Gollapudi_2015). Five other clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories cited the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Hypertrophic cardiomyopathy 2 Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Genomic Medicine Lab, University of California San Francisco	Oct 30, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Apr 11, 2023	- -

Primary dilated cardiomyopathy;C0007194:Hypertrophic cardiomyopathy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

May 12, 2015

The p.Arg141Trp variant in TNNT2 has been reported in 3 individuals with DCM and segregated with disease in 16 affected relative from 2 families (Li 2001, Villa rd 2005) Additionally, the variant occurred de novo in 1 individual with LVNC (K laassan 2008). This variant has also been identified by our laboratory in 10 ind ividuals with cardiomyopathy, most of whom were diagnosed with DCM at very young ages (<10 years), segregated with disease in 1 affected relative, and occurred de novo in 1 individual. This variant was absent from large population studies. In vitro functional studies provide some evidence that the p.Arg141Trp variant m ay impact protein function (Lu 2003, Venkatraman 2003, Venkatraman 2005, Mirza 2 005, Robinson 2007, Liu 2012, Memo 2013, Sommerse 2013). In summary, this varian t meets our criteria to be classified as pathogenic for DCM in an autosomal domi nant manner (http://www.partners.org/personalizedmedicine/LMM) based upon segreg ation studies, absence from controls, and functional evidence. -

Familial isolated dilated cardiomyopathy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Center of Genomic medicine, Geneva, University Hospital of Geneva

Apr 20, 2018

- -

Cardiomyopathy, familial restrictive, 3 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Genome-Nilou Lab

Apr 11, 2023

- -

Primary dilated cardiomyopathy Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Blueprint Genetics

Aug 04, 2014

- -

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

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 17, 2023

This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 141 of the TNNT2 protein (p.Arg141Trp). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with dilated cardiomyopathy (DCM), segregating with the disease in two multigenerational families (PMID: 11684629, 15769782, 21846512, 24992688, 26656454). In at least one individual the variant was observed to be de novo. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 12414). 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) performed at Invitae indicates that this missense variant is expected to disrupt TNNT2 protein function. Experimental studies have shown that this missense change affects TNNT2 function (PMID: 14654368, 18349139, 18606313, 23539503, 24367593). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.54
CardioboostCm	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.34	D
BayesDel_noAF	Pathogenic	0.25
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	.;.;.;.;D;.;.;.;.;.;D;.
Eigen	Uncertain	0.42
Eigen_PC	Uncertain	0.30
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	1.0	.;D;D;D;D;D;D;.;.;D;.;.
M_CAP	Pathogenic	0.88	D
MetaRNN	Pathogenic	0.92	D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.1	.;.;.;.;M;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	A;A;A;A;A;A;A;A;A;A
PrimateAI	Pathogenic	0.80	T
PROVEAN	Pathogenic	-7.0	D;D;.;.;.;.;.;.;D;D;D;D
REVEL	Uncertain	0.62
Sift	Pathogenic	0.0	D;D;.;.;.;.;.;.;D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D;D;D;D;D;D;D;.;D
Polyphen		1.0	.;.;.;.;D;.;.;.;.;.;D;.
Vest4		0.79
MutPred		0.62		.;.;.;.;Loss of methylation at K156 (P = 0.1239);.;.;.;.;.;.;Loss of methylation at K156 (P = 0.1239);
MVP		0.94
MPC		1.5
ClinPred		0.99	D
GERP RS		3.3
Varity_R		0.76
gMVP		0.97

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

LitVar

Other links and lift over

dbSNP: rs74315379; hg19: chr1-201333464;