3-52451292-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM1BP4_Moderate

The NM_003280.3(TNNC1):c.469A>C(p.Met157Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000929 in 1,613,904 control chromosomes in the GnomAD database, with no homozygous occurrence. 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: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000096 ( 0 hom. )

Consequence

TNNC1
NM_003280.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 3.35

Variant links:

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]

TNNC1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 0 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

BP4

Computational evidence support a benign effect (MetaRNN=0.253663).

Transcripts

RefSeq

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

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TNNC1	ENST00000232975.8 linkuse as main transcript	c.469A>C	p.Met157Leu	missense_variant	6/6	1	NM_003280.3	P1

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152068

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.000478

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251070

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135860

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000882

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000958

AC:

AN:

1461836

Hom.:

Cov.:

AF XY:

0.00000825

AC XY:

AN XY:

727210

show subpopulations

Gnomad4 AFR exome

AF:

0.00

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:

0.0000126

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000658

AC:

AN:

152068

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74280

show subpopulations

Gnomad4 AFR

AF:

0.00

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:

0.000478

Alfa

AF:

0.0000282

Hom.:

Bravo

AF:

0.0000113

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Dilated cardiomyopathy 1Z;C2750472:Hypertrophic cardiomyopathy 13

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 09, 2023

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). This variant is present in population databases (rs730880230, gnomAD 0.0009%). This missense change has been observed in individual(s) with hypertrophic cardiomyopathy (PMID: 29121657). ClinVar contains an entry for this variant (Variation ID: 181569). 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. 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. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Mar 06, 2017

This variant is denoted p.Met157Leu (ATG>CTG): c.469 A>C in exon 6 of the TNNC1 gene (NM_003280.2). Mutations in the TNNC1 gene are a rare cause of autosomal dominant familial hypertrophic cardiomyopathy (HCM) and are thought to change calcium sensitivity and heart muscle contraction (Cirino A et al., 2011). Mutation in the TNNC1 gene been reported less frequently in patients with autosomal dominant dilated cardiomyopathy (DCM) (Morgensen J et al., 2004; Hershberger R et al., 2010). The M157L variant has not been published as a mutation or as a benign polymorphism to our knowledge. The M157L variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. While the M157L variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties, this substitution occurs at a position that is conserved in mammals. In silico analysisis inconsistent in its predictions, however at least two models predict this variant is probably damaging to the protein structure/function. A missense mutation in a nearby residue (G159D) has been reported in association with DCM, supporting the functional importance of this region of the protein. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic mutation or a rare benign variant. The variant is found in CARDIOMYOPATHY panel(s). -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 18, 2023

The p.M157L variant (also known as c.469A>C), located in coding exon 6 of the TNNC1 gene, results from an A to C substitution at nucleotide position 469. The methionine at codon 157 is replaced by leucine, an amino acid with highly similar properties. This variant was detected in a hypertrophic cardiomyopathy cohort; however, details were not provided (Viswanathan SK et al. PLoS ONE. 2017;12:e0187948). This alteration was also identified in a subject suspected to have arrhythmogenic right ventricular cardiomyopathy (ARVC) (Forleo C et al. PLoS One, 2017 Jul;12:e0181842). This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.46

BayesDel_addAF

Uncertain

0.095

BayesDel_noAF

Benign

-0.10

Cadd

Uncertain

Dann

Uncertain

0.98

DEOGEN2

Uncertain

0.55

Eigen

Benign

0.032

Eigen_PC

Benign

0.13

FATHMM_MKL

Benign

0.75

LIST_S2

Uncertain

0.92

M_CAP

Uncertain

0.12

MetaRNN

Benign

0.25

MetaSVM

Uncertain

0.42

MutationAssessor

Benign

0.53

MutationTaster

Benign

1.0

PrimateAI

Uncertain

0.72

PROVEAN

Benign

-1.8

REVEL

Uncertain

0.44

Sift

Uncertain

0.027

Sift4G

Benign

0.076

Polyphen

0.067

Vest4

0.36

MutPred

0.54

Loss of disorder (P = 0.0738);

MVP

0.58

MPC

1.0

ClinPred

0.73

GERP RS

2.5

Varity_R

0.73

gMVP

0.79

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over