rs1553651622

Positions:

• chr3-52451288-T-C
• chr3-52451288-T-G

Variant summary

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

The NM_003280.3(TNNC1):​c.473A>G​(p.Lys158Arg) 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 (★). Synonymous variant affecting the same amino acid position (i.e. K158K) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TNNC1 NM_003280.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.33

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 domain EF-hand 4 (size 33) in uniprot entity TNNC1_HUMAN there are 6 pathogenic changes around while only 0 benign (100%) in NM_003280.3
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.32585883).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TNNC1	NM_003280.3	c.473A>G	p.Lys158Arg	missense_variant	6/6	ENST00000232975.8	NP_003271.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TNNC1	ENST00000232975.8	c.473A>G	p.Lys158Arg	missense_variant	6/6	1	NM_003280.3	ENSP00000232975	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

Labcorp Genetics (formerly Invitae), Labcorp

Aug 21, 2021

This sequence change replaces lysine with arginine at codon 158 of the TNNC1 protein (p.Lys158Arg). The lysine residue is moderately conserved and there is a small physicochemical difference between lysine and arginine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with TNNC1-related conditions. 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 tolerated. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.096
BayesDel_addAF	Uncertain	0.056	T
BayesDel_noAF	Benign	-0.16
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.42	T
Eigen	Uncertain	0.27
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Benign	0.63	D
LIST_S2	Benign	0.84	T
M_CAP	Uncertain	0.13	D
MetaRNN	Benign	0.33	T
MetaSVM	Uncertain	0.57	D
MutationAssessor	Benign	0.93	L
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.60	T
PROVEAN	Benign	-0.75	N
REVEL	Uncertain	0.46
Sift	Uncertain	0.0070	D
Sift4G	Benign	0.14	T
Polyphen		0.81	P
Vest4		0.073
MutPred		0.42		Loss of glycosylation at K158 (P = 0.0236);
MVP		0.76
MPC		0.42
ClinPred		0.77	D
GERP RS		4.0
Varity_R		0.42
gMVP		0.59

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: chr3-52485304;