3-52451286-C-T

Variant names:

• chr3-52451286-C-T
• rs896718266
• NM_003280.3:c.475G>A

Variant summary

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

The NM_003280.3(TNNC1):​c.475G>A​(p.Gly159Ser) variant causes a missense change. The variant allele was found at a frequency of 0.00000657 in 152,112 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. G159D) has been classified as Likely pathogenic.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
• Consequence: TNNC1 NM_003280.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.71

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 13 pathogenic changes around while only 0 benign (100%) in NM_003280.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr3-52451285-C-T is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TNNC1	NM_003280.3	c.475G>A	p.Gly159Ser	missense_variant	Exon 6 of 6	ENST00000232975.8	NP_003271.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TNNC1	ENST00000232975.8	c.475G>A	p.Gly159Ser	missense_variant	Exon 6 of 6	1	NM_003280.3	ENSP00000232975.3
TNNC1	ENST00000496590.1	c.*129G>A		downstream_gene_variant		2		ENSP00000420596.1
TNNC1	ENST00000461086.1	n.*153G>A		downstream_gene_variant		2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152112 Hom.: 0 Cov.: 33

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251014 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135850

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 Cov.: 31

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152112 Hom.: 0 Cov.: 33 AF XY: 0.0000135 AC XY: 1 AN XY: 74290

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: 0.0000147

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000282 Hom.: 0

Bravo AF: 0.0000151

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Oct 11, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: TNNC1 c.475G>A (p.Gly159Ser) results in a non-conservative amino acid change located in the EF-hand domain (IPR002048) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 251014 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.475G>A in individuals affected with Cardiomyopathy and no experimental evidence demonstrating its impact on protein function have been reported. No submitters have cited clinical-significance assessments for this variant to ClinVar. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.30
BayesDel_addAF	Uncertain	0.083	D
BayesDel_noAF	Benign	-0.12
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.38	T
Eigen	Uncertain	0.28
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.92	D
M_CAP	Uncertain	0.21	D
MetaRNN	Uncertain	0.48	T
MetaSVM	Uncertain	0.62	D
MutationAssessor	Benign	0.14	N
PrimateAI	Uncertain	0.64	T
PROVEAN	Benign	-0.51	N
REVEL	Uncertain	0.51
Sift	Benign	0.13	T
Sift4G	Benign	0.13	T
Polyphen		1.0	D
Vest4		0.45
MutPred		0.51		Gain of phosphorylation at G159 (P = 0.0302);
MVP		0.72
MPC		1.4
ClinPred		0.84	D
GERP RS		4.3
Varity_R		0.41
gMVP		0.81

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs896718266; hg19: chr3-52485302;