rs730881058

Positions:

• chr3-52451799-C-A
• chr3-52451799-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PM5

The ENST00000232975.8(TNNC1):​c.262G>T​(p.Asp88Tyr) variant causes a missense 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D88N) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TNNC1 ENST00000232975.8 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.91

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 Likely_pathogenic. Variant got 6 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 ENST00000232975.8
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr3-52451799-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 181563.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TNNC1	NM_003280.3	c.262G>T	p.Asp88Tyr	missense_variant	4/6	ENST00000232975.8	NP_003271.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TNNC1	ENST00000232975.8	c.262G>T	p.Asp88Tyr	missense_variant	4/6	1	NM_003280.3	ENSP00000232975	P1
TNNC1	ENST00000496590.1	c.130G>T	p.Asp44Tyr	missense_variant	3/4	2		ENSP00000420596
TNNC1	ENST00000461086.1	n.193G>T		non_coding_transcript_exon_variant	1/2	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Sep 20, 2017

The D88Y variant of uncertain significance in the TNNC1 gene has not been published as pathogenic or been reported as benign to our knowledge. The D88Y variant is not observed in large population cohorts (Lek et al., 2016). The D88Y variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position where amino acids with similar properties to aspartic acid (D) are tolerated across species. In silico analysis predicts this variant is probably damaging to the protein structure/function. However, this variant lacks observation in a significant number of affected individuals, segregation data, and functional evidence, which would further clarify its pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.57
BayesDel_addAF	Pathogenic	0.29	D
BayesDel_noAF	Pathogenic	0.18
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.50	T;T
Eigen	Uncertain	0.62
Eigen_PC	Uncertain	0.65
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.92	D;D
M_CAP	Uncertain	0.17	D
MetaRNN	Uncertain	0.70	D;D
MetaSVM	Pathogenic	0.80	D
MutationAssessor	Benign	1.9	L;.
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.83	D
PROVEAN	Uncertain	-2.4	N;D
REVEL	Pathogenic	0.69
Sift	Uncertain	0.018	D;D
Sift4G	Uncertain	0.0040	D;.
Polyphen		0.97	D;.
Vest4		0.65
MutPred		0.34		Loss of disorder (P = 0.0143);.;
MVP		0.71
MPC		1.3
ClinPred		0.98	D
GERP RS		5.6
Varity_R		0.68
gMVP		0.92

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: rs730881058; hg19: chr3-52485815;