rs1553651630

Positions:

• chr3-52451412-CGTT-C

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PM4_Supporting

The NM_003280.3(TNNC1):​c.430_432del​(p.Asn144del) variant causes a inframe deletion change. The variant allele was found at a frequency of 0.00000274 in 1,461,858 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. N144N) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: TNNC1 NM_003280.3 inframe_deletion
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 5.03

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 5 ACMG points.

• PM1: In a chain Troponin C, slow skeletal and cardiac muscles (size 160) in uniprot entity TNNC1_HUMAN there are 27 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. Strenght limited to Supporting due to length of the change: 1aa.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TNNC1	NM_003280.3	c.430_432del	p.Asn144del	inframe_deletion	5/6	ENST00000232975.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TNNC1	ENST00000232975.8	c.430_432del	p.Asn144del	inframe_deletion	5/6	1	NM_003280.3	P1
TNNC1	ENST00000496590.1			incomplete_terminal_codon_variant, coding_sequence_variant, 3_prime_UTR_variant	4/4	2
TNNC1	ENST00000461086.1			downstream_gene_variant		2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461858 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 727228

Gnomad4 AFR exome AF: 0.0000299

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: 0.00000180

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jan 30, 2018

A variant of uncertain significance has been identified in the TNNC1 gene. The c.430_432delAAC variant has not been published as pathogenic or been reported as benign to our knowledge. This variant is not observed in large population cohorts (Lek et al., 2016). The c.430_432del AAC results in the deletion of a single amino acid residue, asparagine 144, and does not results in a shift in reading frame, an abnormal, truncated protein product, or loss of protein from this allele through nonsense-mediated mRNA decay. Nevertheless, in-silico analyses, including protein predictors and evolutionary conservation, support a deleterious effect. -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 03, 2023

This variant, c.430_432del, results in the deletion of 1 amino acid(s) of the TNNC1 protein (p.Asn144del), but otherwise preserves the integrity of the reading frame. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TNNC1-related conditions. 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. Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. ClinVar contains an entry for this variant (Variation ID: 504180). -

Computational scores

Source: dbNSFP v4.3

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: rs1553651630; hg19: chr3-52485428;