19-55154158-G-C

Position:

• chr19-55154158-G-C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_000363.5(TNNI3):​c.421C>G​(p.Arg141Gly) 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R141W) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: TNNI3 NM_000363.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 0.403

Genes affected

TNNI3 (HGNC:11947): (troponin I3, cardiac type) Troponin I (TnI), along with troponin T (TnT) and troponin C (TnC), is one of 3 subunits that form the troponin complex of the thin filaments of striated muscle. TnI is the inhibitory subunit; blocking actin-myosin interactions and thereby mediating striated muscle relaxation. The TnI subfamily contains three genes: TnI-skeletal-fast-twitch, TnI-skeletal-slow-twitch, and TnI-cardiac. This gene encodes the TnI-cardiac protein and is exclusively expressed in cardiac muscle tissues. Mutations in this gene cause familial hypertrophic cardiomyopathy type 7 (CMH7) and familial restrictive cardiomyopathy (RCM). Troponin I is useful in making a diagnosis of heart failure, and of ischemic heart disease. An elevated level of troponin is also now used as indicator of acute myocardial injury in patients hospitalized with moderate/severe Coronavirus Disease 2019 (COVID-19). Such elevation has also been associated with higher risk of mortality in cardiovascular disease patients hospitalized due to COVID-19. [provided by RefSeq, Aug 2020]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 12 uncertain in NM_000363.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr19-55154157-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 43381.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.953

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TNNI3	NM_000363.5	c.421C>G	p.Arg141Gly	missense_variant	7/8	ENST00000344887.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TNNI3	ENST00000344887.10	c.421C>G	p.Arg141Gly	missense_variant	7/8	1	NM_000363.5	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Aug 14, 2019

This missense variant replaces arginine with glycine at codon 141 of the TNNI3 protein. Computational prediction tools and conservation analyses are inconclusive regarding the impact of this variant on the protein function. Computational splicing tools suggest that this variant may not impact RNA splicing. To our knowledge, functional assays have not been performed for this variant. This variant has been reported in an individual referred for cardiomyopathy test, who showed no left ventricular hypertrophy (PMID: 24704860). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). A different missense variant occurring at the same codon, p.Arg141Gln, is associated with disease (Clinvar variation ID 43381), suggesting that arginine at this position is important for the protein function. 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. -

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 17, 2023

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. This variant disrupts the p.Arg141 amino acid residue in TNNI3. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 12707239, 18403758, 19645627, 23283745). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. ClinVar contains an entry for this variant (Variation ID: 920147). This variant has not been reported in the literature in individuals affected with TNNI3-related conditions. 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 141 of the TNNI3 protein (p.Arg141Gly). -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 20, 2019

The p.R141G variant (also known as c.421C>G), located in coding exon 7 of the TNNI3 gene, results from a C to G substitution at nucleotide position 421. The arginine at codon 141 is replaced by glycine, an amino acid with dissimilar properties. A different alteration located at the same position, p.R141Q, has been detected in several individuals with hypertrophic cardiomyopathy (HCM) (Richard P et al. Circulation. 2003;107:2227-32; Van Driest SL et al. Circulation. 2003;108:445-51; van den Wijngaard A et al. Neth Heart J. 2011;19:344-51; Rani DS et al. BMC Med. Genet. 2012;13:69; Zou Y et al. Mol Biol Rep. 2013;40:3969-76; Landry CH et al. N Engl J Med. 2017;377(20):1943-1953; Curila K et al. Genet Test Mol Biomarkers. 2009;13:647-50), was detected in the homozygous state in an individual with severe biventricular hypertrophy (Mogensen J et al. J Am Coll Cardiol. 2004;44:2315-25), has co-occurred with other variants in cardiac-related genes in affected individuals (Morita H et al. N Engl J Med. 2008;358:1899-908; Santos S et al. BMC Med Genet. 2012;13:17), and has been detected in unaffected relatives (Mogensen J et al. J Am Coll Cardiol. 2004;44:2315-25). In addition, a different alteration located at the same position, p.R141W, has been detected in one individual with hypertrophic cardiomyopathy (HCM) (Viswanathan SK et al. PLoS ONE, 2017 Nov;12:e0187948). This amino acid position is well 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 the p.R141G alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
CardioboostCm	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.21
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.96	D;D
Eigen	Uncertain	0.24
Eigen_PC	Benign	0.12
FATHMM_MKL	Benign	0.41	N
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Pathogenic	0.43	D
MetaRNN	Pathogenic	0.95	D;D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Uncertain	2.9	M;.
MutationTaster	Benign	0.65	D;D
PrimateAI	Uncertain	0.67	T
PROVEAN	Pathogenic	-5.7	D;.
REVEL	Pathogenic	0.73
Sift	Uncertain	0.0010	D;.
Sift4G	Uncertain	0.0020	D;D
Polyphen		0.96	D;.
Vest4		0.80
MutPred		0.79		Loss of helix (P = 0.0237);.;
MVP		0.94
MPC		1.8
ClinPred		0.98	D
GERP RS		2.4
Varity_R		0.98

Splicing

Name	Calibrated prediction	Score	Prediction
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

LitVar

Other links and lift over

dbSNP: rs730881071; hg19: chr19-55665526;