1-201364300-C-T

Position:

• chr1-201364300-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_001276345.2(TNNT2):​c.487G>A​(p.Ala163Thr) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.0000131 in 152,226 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: 𝑓 0.000013 (0 hom., cov: 33)
• Consequence: TNNT2 NM_001276345.2 missense, splice_region
• Scores: Splicing: ADA: 0.5485
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 5.73

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 Likely_pathogenic. Variant got 6 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
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.855

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TNNT2	NM_001276345.2	c.487G>A	p.Ala163Thr	missense_variant, splice_region_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.487G>A	p.Ala163Thr	missense_variant, splice_region_variant	11/17		NM_001276345.2	ENSP00000499593	A2

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152226 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000482

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152226 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74382

Gnomad4 AFR AF: 0.0000482

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000189

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Mar 13, 2014

The Ala153Thr variant in TNNT2 has not been previously reported in individuals w ith cardiomyopathy. Data from large population studies are insufficient to asses s the frequency of this variant. Alanine (Ala) at position 153 is conserved in m ammals though not in evolutionarily distant species. The change to threonine (Th r) was predicted to be pathogenic using a computational tool clinically validate d by our laboratory. This tool's pathogenic prediction is estimated to be correc t 94% of the time (Jordan 2011). In summary, additional information is needed to fully assess the clinical significance of this variant. -

Primary dilated cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Mar 14, 2024

- -

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

Mar 24, 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. 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: 179660). This missense change has been observed in individual(s) with hypertrophic cardiomyopathy (PMID: 25132132). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 153 of the TNNT2 protein (p.Ala153Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
CardioboostCm	Uncertain	0.72
BayesDel_addAF	Pathogenic	0.16	D
BayesDel_noAF	Uncertain	0.0
CADD	Pathogenic	29
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.90	.;.;.;.;D;.;.;.;.;.;D;.
Eigen	Uncertain	0.54
Eigen_PC	Uncertain	0.51
FATHMM_MKL	Uncertain	0.82	D
LIST_S2	Uncertain	0.95	.;D;D;D;D;D;D;.;.;D;.;.
M_CAP	Pathogenic	0.90	D
MetaRNN	Pathogenic	0.86	D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Uncertain	2.3	.;.;.;.;M;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D
PrimateAI	Uncertain	0.56	T
PROVEAN	Uncertain	-3.0	D;D;.;.;.;.;.;.;D;D;D;D
REVEL	Pathogenic	0.78
Sift	Uncertain	0.0020	D;D;.;.;.;.;.;.;D;D;D;D
Sift4G	Benign	0.26	T;T;T;T;T;T;T;T;T;T;.;T
Polyphen		0.77, 0.99	.;.;.;.;P;.;.;.;.;.;D;.
Vest4		0.42
MVP		0.92
MPC		1.3
ClinPred		0.97	D
GERP RS		4.3
Varity_R		0.19
gMVP		0.79

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.55
dbscSNV1_RF	Benign	0.67
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: rs727505030; hg19: chr1-201333428;