rs397516848
Variant summary
Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM1
The NM_003280.3(TNNC1):c.442A>G(p.Ile148Val) variant causes a missense change. The variant allele was found at a frequency of 0.000013 in 1,614,028 control chromosomes in the GnomAD database, including 1 homozygotes. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. I148I) has been classified as Likely benign.
Frequency
Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000013 ( 1 hom. )
Consequence
TNNC1
NM_003280.3 missense
NM_003280.3 missense
Scores
2
4
13
Clinical Significance
Conservation
PhyloP100: 4.93
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]
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ACMG classification
Classification made for transcript
Verdict is Uncertain_significance. Variant got 2 ACMG points.
PM1
?
In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_003280.3
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
---|---|---|---|---|---|---|---|
TNNC1 | NM_003280.3 | c.442A>G | p.Ile148Val | missense_variant | 5/6 | ENST00000232975.8 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
TNNC1 | ENST00000232975.8 | c.442A>G | p.Ile148Val | missense_variant | 5/6 | 1 | NM_003280.3 | P1 | |
TNNC1 | ENST00000496590.1 | downstream_gene_variant | 2 | ||||||
TNNC1 | ENST00000461086.1 | downstream_gene_variant | 2 |
Frequencies
GnomAD3 genomes ? AF: 0.0000131 AC: 2AN: 152164Hom.: 0 Cov.: 33
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GnomAD3 exomes AF: 0.00000797 AC: 2AN: 250838Hom.: 0 AF XY: 0.0000147 AC XY: 2AN XY: 135792
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GnomAD4 exome AF: 0.0000130 AC: 19AN: 1461864Hom.: 1 Cov.: 31 AF XY: 0.0000110 AC XY: 8AN XY: 727230
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ClinVar
Significance: Uncertain significance
Submissions summary: Uncertain:4
Revision: criteria provided, multiple submitters, no conflicts
LINK: link
Submissions by phenotype
not specified Uncertain:2
Uncertain significance, criteria provided, single submitter | clinical testing | Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine | May 25, 2012 | The Ile148Val variant in TNNC1 has been identified in 1 individual with DCM and was absent from 492 control chromosomes (Hershberger 2010). Studies showed that this variant exhibited decreased calcium sensitivity and altered response to PKA phosphorylation, but these in vitro assays may not accurately represent biologi cal function (Pinto 2011). Computational analyses (biochemical amino acid proper ties, conservation,AlignGVGD, and SIFT) suggest that the Ile148Val variant may n ot impact the protein, though this information is not predictive enough to rule out pathogenicity. In summary, the available information for this variant is con flicting and additional information is needed to fully assess its clinical signi ficance. - |
Uncertain significance, criteria provided, single submitter | clinical testing | Women's Health and Genetics/Laboratory Corporation of America, LabCorp | Jul 06, 2021 | Variant summary: TNNC1 c.442A>G (p.Ile148Val) results in a conservative amino acid change located in the EF-hand domain (IPR002048) of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 250838 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.442A>G has been reported in the literature in individuals affected with Cardiomyopathy and SUD (e.g. Hershberger_2010, Pinto_2011, Ng_2013, Pugh_2014, Dewar_2017). These reports do not provide unequivocal conclusions about association of the variant with Cardiomyopathy. A co-occurrence with a likely pathogenic variant has been reported (DSP c.2848_2849insA, p.Ile950AsnfsX3; Pugh_2014). Experimental evidence evaluating an impact on protein function demonstrated pig skinned fibers reconstituted with the variant and incubated with PKA, to have a reduced effect of PKA phosphorylation on myofilament Ca2+ desensitization compared with WT. Nevertheless, the variant was similar to WT in fully activating or inhibiting the actomyosin ATPase activity in the presence and absence of Ca2+, while it did not affect the maximal force recovery in the presence or absence of PKA compared with WT (Pinto_2011). These data do not allow convincing conclusions about the variant effect. Two ClinVar submitters (evaluation after 2014) cite the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. - |
Dilated cardiomyopathy 1Z;C2750472:Hypertrophic cardiomyopathy 13 Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Invitae | May 15, 2023 | 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 have shown that this missense change affects TNNC1 function (PMID: 21832052). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. ClinVar contains an entry for this variant (Variation ID: 44682). This missense change has been observed in individual(s) with clinical features of dilated cardiomyopathy (PMID: 20215591, 24503780, 27532257, 28807990). This variant is present in population databases (rs397516848, gnomAD 0.003%). This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 148 of the TNNC1 protein (p.Ile148Val). - |
Primary dilated cardiomyopathy Uncertain:1
Uncertain significance, criteria provided, single submitter | research | Biesecker Lab/Clinical Genomics Section, National Institutes of Health | Apr 05, 2018 | - - |
Computational scores
Source:
Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
BayesDel_addAF
Benign
T
BayesDel_noAF
Benign
Cadd
Uncertain
Dann
Uncertain
DEOGEN2
Benign
T
Eigen
Benign
Eigen_PC
Benign
FATHMM_MKL
Pathogenic
D
LIST_S2
Uncertain
D
M_CAP
Benign
D
MetaRNN
Uncertain
D
MetaSVM
Benign
T
MutationAssessor
Benign
L
MutationTaster
Benign
D
PrimateAI
Pathogenic
T
PROVEAN
Benign
N
REVEL
Uncertain
Sift
Benign
T
Sift4G
Benign
T
Polyphen
B
Vest4
MutPred
Loss of catalytic residue at I148 (P = 0.1114);
MVP
MPC
ClinPred
T
GERP RS
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gMVP
Splicing
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SpliceAI score (max)
Details are displayed if max score is > 0.2
Find out detailed SpliceAI scores and Pangolin per-transcript scores at