chr3-52452132-T-TC

Variant names:

• chr3-52452132-T-TC
• rs1060502609
• NM_003280.3:c.175dupG

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_003280.3(TNNC1):​c.175dupG​(p.Glu59GlyfsTer5) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TNNC1 NM_003280.3 frameshift
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 7.91
• Publications: 1 publications found

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 Gene-Disease associations (from GenCC):

• dilated cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• dilated cardiomyopathy 1Z

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• hypertrophic cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• hypertrophic cardiomyopathy 13

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia, G2P
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• arrhythmogenic right ventricular cardiomyopathy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TNNC1	NM_003280.3	c.175dupG	p.Glu59GlyfsTer5	frameshift_variant	Exon 3 of 6	ENST00000232975.8	NP_003271.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TNNC1	ENST00000232975.8	c.175dupG	p.Glu59GlyfsTer5	frameshift_variant	Exon 3 of 6	1	NM_003280.3	ENSP00000232975.3
TNNC1	ENST00000496590.1	c.43dupG	p.Glu15GlyfsTer5	frameshift_variant	Exon 2 of 4	2		ENSP00000420596.1
TNNC1	ENST00000461086.1	n.-142dupG		upstream_gene_variant		2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Dilated cardiomyopathy 1Z;C2750472:Hypertrophic cardiomyopathy 13 Uncertain:2

Dec 14, 2021

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jun 17, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The current clinical and genetic evidence is not sufficient to establish whether loss-of-function variants in TNNC1 cause disease. Therefore, this variant has been classified as a Variant of Uncertain Significance. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a TNNC1-related disease. This sequence change inserts 1 nucleotide in exon 3 of the TNNC1 mRNA (c.175dupG), causing a frameshift at codon 59. This creates a premature translational stop signal (p.Glu59Glyfs*5) and is expected to result in an absent or disrupted protein product. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.9

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs1060502609; hg19: chr3-52486148;