rs139705141

Positions:

• chr1-201373245-T-C
• chr1-201373245-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 4P and 4B. PM1 PM2 BP4_Strong

The NM_001276345.2(TNNT2):​c.10A>G​(p.Ile4Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,842 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign 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. I4L) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TNNT2 NM_001276345.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.954

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 0 ACMG points.

• PM1: In a chain Troponin T, cardiac muscle (size 296) in uniprot entity TNNT2_HUMAN there are 176 pathogenic changes around while only 18 benign (91%) in NM_001276345.2
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.06438592).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TNNT2	NM_001276345.2	c.10A>G	p.Ile4Val	missense_variant	2/17	ENST00000656932.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TNNT2	ENST00000656932.1	c.10A>G	p.Ile4Val	missense_variant	2/17		NM_001276345.2	A2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461842 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727220

Gnomad4 AFR exome AF: 0.0000299

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: 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

Feb 18, 2021

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 output the following: SIFT: "Tolerated"; PolyPhen-2: "Not Available"; Align-GVGD: "Class C0". The valine amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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 isoleucine with valine at codon 4 of the TNNT2 protein (p.Ile4Val). The isoleucine residue is weakly conserved and there is a small physicochemical difference between isoleucine and valine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.063
CardioboostCm	Benign	0.010
BayesDel_addAF	Benign	-0.0020	T
BayesDel_noAF	Benign	-0.24
CADD	Benign	0.049
DANN	Benign	0.75
DEOGEN2	Benign	0.32	.;.;.;.;T;.;.;.;T;.;.;T
Eigen	Benign	-1.5
Eigen_PC	Benign	-1.6
FATHMM_MKL	Benign	0.041	N
LIST_S2	Benign	0.34	.;T;T;T;T;T;.;T;.;.;T;.
M_CAP	Uncertain	0.099	D
MetaRNN	Benign	0.064	T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	0.033	D
MutationAssessor	Benign	-0.76	N;N;.;N;N;.;N;N;.;.;.;.
MutationTaster	Benign	1.0	N;N;N;N;N;N;N;N;N;N
PrimateAI	Benign	0.27	T
PROVEAN	Benign	0.33	N;N;N;N;N;N;N;N;N;N;N;N
REVEL	Uncertain	0.34
Sift	Benign	0.14	T;T;T;T;T;T;T;T;T;T;T;T
Sift4G	Benign	0.49	T;T;T;T;T;T;T;T;.;T;T;.
Vest4		0.091
MVP		0.62
MPC		0.42
ClinPred		0.19	T
GERP RS		-8.0
Varity_R		0.013
gMVP		0.35

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: rs139705141; hg19: chr1-201342373;