NM_003280.3:c.74_82delACATCTTCG

Variant names:

• chr3-52452225-ACGAAGATGT-A
• rs727503496
• NM_003280.3:c.74_82delACATCTTCG

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM1 PM2 PM4 PP3

The NM_003280.3(TNNC1):​c.74_82delACATCTTCG​(p.Asp25_Phe27del) variant causes a disruptive inframe deletion 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 (★). Synonymous variant affecting the same amino acid position (i.e. D25D) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TNNC1 NM_003280.3 disruptive_inframe_deletion
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.32
• Publications: 0 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: Likely_pathogenic. The variant received 7 ACMG points.

• PM1: In a domain EF-hand 1 (size 35) in uniprot entity TNNC1_HUMAN there are 4 pathogenic changes around while only 0 benign (100%) in NM_003280.3
• PM2: Very rare variant in population databases, with high coverage
• PM4: Nonframeshift variant in NON repetitive region in NM_003280.3.
• PP3: No computational evidence supports a deleterious effect, but strongly conserved according to phyloP

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TNNC1	NM_003280.3	c.74_82delACATCTTCG	p.Asp25_Phe27del	disruptive_inframe_deletion	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.74_82delACATCTTCG	p.Asp25_Phe27del	disruptive_inframe_deletion	Exon 3 of 6	1	NM_003280.3	ENSP00000232975.3
TNNC1	ENST00000496590.1	c.-59_-51delACATCTTCG		5_prime_UTR_variant	Exon 2 of 4	2		ENSP00000420596.1
TNNC1	ENST00000461086.1	n.-243_-235delACATCTTCG		upstream_gene_variant		2

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Sep 20, 2013

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant classified as Uncertain Significance - Favor Pathogenic. The Asp25_Phe27 del variant in TNNC1 has not been previously reported in individuals with cardio myopathy. Data from large population studies is insufficient to assess the frequ ency of this variant. This variant leads to a deletion of 3 amino acids beginnin g at position 25 and is not predicted to alter the protein reading-frame. While this deletion is likely to impact the protein, it is unclear if that impact woul d result in disease. In addition, the phenotypic spectrum of disease-causing TNN C1 variants is currently not yet well defined. Additional studies are needed to fully assess its clinical significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		9.3

Splicing

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

Other links and lift over

dbSNP: rs727503496; hg19: chr3-52486241;