3-52451292-T-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM1 PM2 BP4

The NM_003280.3(TNNC1):c.469A>T(p.Met157Leu) 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 benign outcome for this variant. 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. M157R) 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:2
• Conservation: PhyloP100: 3.35

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 Uncertain_significance. Variant got 3 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
• BP4: Computational evidence support a benign effect (MetaRNN=0.2686298).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TNNC1	NM_003280.3	c.469A>T	p.Met157Leu	missense_variant	6/6	ENST00000232975.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TNNC1	ENST00000232975.8	c.469A>T	p.Met157Leu	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:2

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

Apr 08, 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: 180550). This variant has not been reported in the literature in individuals affected with TNNC1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces methionine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 157 of the TNNC1 protein (p.Met157Leu). -

Primary dilated cardiomyopathy Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Blueprint Genetics

Sep 29, 2014

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.46
BayesDel_addAF	Uncertain	0.095	D
BayesDel_noAF	Benign	-0.10
Cadd	Uncertain	24
Dann	Uncertain	0.98
DEOGEN2	Uncertain	0.55	D
Eigen	Benign	0.032
Eigen_PC	Benign	0.13
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.92	D
M_CAP	Uncertain	0.13	D
MetaRNN	Benign	0.27	T
MetaSVM	Uncertain	0.42	D
MutationAssessor	Benign	0.53	N
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.72	T
PROVEAN	Benign	-1.8	N
REVEL	Uncertain	0.44
Sift	Uncertain	0.027	D
Sift4G	Benign	0.076	T
Polyphen		0.067	B
Vest4		0.36
MutPred		0.54		Loss of disorder (P = 0.0738);
MVP		0.58
MPC		1.0
ClinPred		0.80	D
GERP RS		2.5
Varity_R		0.73
gMVP		0.79

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: rs730880230; hg19: chr3-52485308;