3-52451291-A-C

Variant summary

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

The NM_003280.3(TNNC1):c.470T>G(p.Met157Arg) 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M157L) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TNNC1 NM_003280.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.27

Genes affected

TNNC1 (HGNC:11943): (troponin C1, slow skeletal and cardiac type) Troponin is a central regulatory protein of striated muscle contraction, and together with tropomyosin, is located on the actin filament. Troponin consists of 3 subunits: TnI, which is the inhibitor of actomyosin ATPase; TnT, which contains the binding site for tropomyosin; and TnC, the protein encoded by this gene. The binding of calcium to TnC abolishes the inhibitory action of TnI, thus allowing the interaction of actin with myosin, the hydrolysis of ATP, and the generation of tension. Mutations in this gene are associated with cardiomyopathy dilated type 1Z. [provided by RefSeq, Oct 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_003280.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.889

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TNNC1	NM_003280.3	c.470T>G	p.Met157Arg	missense_variant	6/6	ENST00000232975.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TNNC1	ENST00000232975.8	c.470T>G	p.Met157Arg	missense_variant	6/6	1	NM_003280.3	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Dilated cardiomyopathy 1Z;C2750472:Hypertrophic cardiomyopathy 13 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 28, 2021

This variant is not present in population databases (ExAC no frequency). 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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. This variant has not been reported in the literature in individuals affected with TNNC1-related conditions. This sequence change replaces methionine with arginine at codon 157 of the TNNC1 protein (p.Met157Arg). The methionine residue is highly conserved and there is a moderate physicochemical difference between methionine and arginine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.44
Cadd	Pathogenic	26
Dann	Uncertain	0.98
DEOGEN2	Pathogenic	0.81	D
Eigen	Uncertain	0.59
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.91	D
M_CAP	Pathogenic	0.57	D
MetaRNN	Pathogenic	0.89	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.3	M
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.76	T
PROVEAN	Uncertain	-3.7	D
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		0.82	P
Vest4		0.75
MutPred		0.70		Loss of stability (P = 0.0213);
MVP		0.95
MPC		1.7
ClinPred		0.99	D
GERP RS		2.9
Varity_R		0.96
gMVP		0.98

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr3-52485307;