rs757664792

Positions:

• chr1-201359242-C-G
• chr1-201359242-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The NM_001276345.2(TNNT2):​c.865G>C​(p.Gly289Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★). Another nucleotide change resulting in same amino acid change has been previously reported as Uncertain significancein ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G289E) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TNNT2 NM_001276345.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.34

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 Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_001276345.2
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TNNT2	NM_001276345.2	c.865G>C	p.Gly289Arg	missense_variant	17/17	ENST00000656932.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TNNT2	ENST00000656932.1	c.865G>C	p.Gly289Arg	missense_variant	17/17		NM_001276345.2	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 20, 2018

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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with TNNT2-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces glycine with arginine at codon 279 of the TNNT2 protein (p.Gly279Arg). The glycine residue is weakly conserved and there is a moderate physicochemical difference between glycine and arginine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
CardioboostCm	Benign	0.061
BayesDel_addAF	Uncertain	0.15	D
BayesDel_noAF	Uncertain	-0.020
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.80	.;.;.;.;D;.;.;.;.;.
Eigen	Uncertain	0.55
Eigen_PC	Uncertain	0.46
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.95	.;D;D;D;D;D;D;.;.;D
M_CAP	Pathogenic	0.73	D
MetaRNN	Uncertain	0.57	D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.34	D
MutationAssessor	Uncertain	2.2	.;.;.;.;M;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D
PrimateAI	Uncertain	0.77	T
PROVEAN	Uncertain	-3.2	D;D;.;.;.;.;D;.;D;D
REVEL	Uncertain	0.48
Sift	Uncertain	0.013	D;D;.;.;.;.;T;.;D;D
Sift4G	Uncertain	0.0030	D;D;D;D;D;D;D;D;D;D
Polyphen		1.0	.;.;.;.;D;.;.;.;.;.
Vest4		0.59
MutPred		0.25		.;.;.;.;Gain of methylation at G289 (P = 0.0239);.;.;.;.;.;
MVP		0.94
MPC		1.6
ClinPred		0.99	D
GERP RS		4.0
Varity_R		0.29
gMVP		0.45

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: rs757664792; hg19: chr1-201328370;