17-39665918-G-C
Variant summary
Our verdict is Benign. Variant got -13 ACMG points: 0P and 13B. BP4_StrongBP6BS1BS2
The NM_003673.4(TCAP):āc.313G>Cā(p.Glu105Gln) variant causes a missense change. The variant allele was found at a frequency of 0.0011 in 1,612,906 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_003673.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Benign. Variant got -13 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000677 AC: 103AN: 152214Hom.: 1 Cov.: 32
GnomAD3 exomes AF: 0.000510 AC: 127AN: 248982Hom.: 0 AF XY: 0.000525 AC XY: 71AN XY: 135172
GnomAD4 exome AF: 0.00115 AC: 1676AN: 1460574Hom.: 2 Cov.: 30 AF XY: 0.00108 AC XY: 787AN XY: 726612
GnomAD4 genome AF: 0.000676 AC: 103AN: 152332Hom.: 1 Cov.: 32 AF XY: 0.000524 AC XY: 39AN XY: 74472
ClinVar
Submissions by phenotype
not provided Uncertain:4Benign:3
TCAP: BP4, BS2 -
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This variant is associated with the following publications: (PMID: 31303467, 24037902, 23861362, 30871747) -
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not specified Uncertain:2Benign:2
The p.Glu105Gln variant in TCAP has not been previously reported in individuals with cardiomyopathy, but has been identified in 36/62742 European chromosomes by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP r s146906267). Computational prediction tools and conservation analysis suggest th at this variant may not impact the protein, though this information is not predi ctive enough to rule out pathogenicity. In summary, the clinical significance of the p.Glu105Gln variant is uncertain. -
Variant summary: TCAP c.313G>C (p.Glu105Gln) results in a conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00051 in 248982 control chromosomes. The observed variant frequency is approximately 20 fold of the estimated maximal expected allele frequency for a pathogenic variant in TCAP causing Cardiomyopathy phenotype (2.5e-05). c.313G>C has been reported in the literature in individuals affected with hypertrophic or dilated cardiomyopathy (example, Earle_2015, Martins_2019), as a VUS with non-informative segregation along with a VUS in TNNT2 gene in an individual with dilated cardiomyopathy (example, Sousa_2019) and identified once in a whole exome sequencing study with participants who were not pre-selected for a personal or family history of arrhythmia, cardiomyopathy or sudden cardiac death (example, Ng_2013). These report(s) do not provide unequivocal conclusions about association of the variant with Cardiomyopathy. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 26332198, 31303467, 23861362, 30871747). ClinVar contains an entry for this variant (Variation ID: 191776). Based on the evidence outlined above, the variant was classified as likely benign. -
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Note this variant was found in clinical genetic testing performed by one or more labs who may also submit to ClinVar. Thus any internal case data may overlap with the internal case data of other labs. The interpretation reviewed below is that of the Stanford Center for Inherited Cardiovascular Disease. p.Glu105Gln (c.313 G>C, E105Q) in the TCAP gene (NM_003673.3) TCAP encodes telethonin, which is a component of the z-disc. Variants in TCAP have been reported with cardiomyopathy, though the evidence that they cause cardiomyopathy is fairly weak. Using a candidate gene approach, Hayashi et al (2004) sequenced TCAP in a cohort of 346 HCM patients and 146 DCM patients from Asia. They found two different missense variants in two different families with HCM and in each family the variant was present in two affected first degree relatives (note that one of these variants is present in 2 of 6500 individuals in NHLBI ESP). They found another missense variant in a patient with DCM. The variant was inherited from his unaffected father, not his mother, who had HCM. Again with a candidate gene approach, Mike Ackerman's group sequenced z-disc genes and found three novel TCAP variants in 4 of 398 patients with HCM in their Mayo cohort. This included two missense variants and one in-frame single amino acid deletion.Variants in this gene have also been reported with limb girdle muscular dystrophy (Moreira et al 2000). Reviewing the NHLBI ESP exome variant server, 8 of ~6500 (0.1%) individuals have a rare missense variant (present in 1-3 individuals). We consider it a variant of uncertain significance, given the lack of case data, the weak gene level evidence, and the presence in general population samples. The variant appears to be novel. Polyphen predicts the variant to be possibly damaging. The glutamate at codon 105 is highly, though not completely, conserved across species, as are neighboring amino acids. The Grantham score is 29. Another variant at the same codon (p.Glu105Lys) was reported in one individual in a French Canadian cohort of 96 individuals with DCM (Hirtle-Lewis et al 2013). In total, the variant has been seen in 7 of 7972 individuals from publicly available datasets. The variant was reported online in 5 of 4295 Caucasian individuals and 1 of 2203 African-American individuals in the NHLBI Exome Sequencing Project dataset (as of April 22nd, 2014). The phenotype of those individuals is not publicly available. The dataset is comprised of multiple cohorts, some of which were recruited from the general population, others were enriched for common cardiovascular disease. Note that other variants with strong evidence for pathogenicity have been seen at similar frequencies in this dataset so this does not necessarily rule out pathogenicity (Pan et al 2012). Per the GeneDx report, it is also present at low frequency in the 1000 genomes dataset. The ClinSeq group reported that they observed the variant in 1 of 1474 individuals (Ng et al 2013). The variant is listed in dbSNP (rs146906267), with reference to the NHLBI ESP, 1000 genomes, and ClinSeq data -
Primary familial hypertrophic cardiomyopathy Uncertain:1
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Hypertrophic cardiomyopathy 25 Uncertain:1
This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. However, the evidence from the literature, in combination with allele frequency data from public databases where available, was not sufficient to rule this variant in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
Primary familial hypertrophic cardiomyopathy;C4225408:Hypertrophic cardiomyopathy 25 Uncertain:1
This sequence change replaces glutamic acid, which is acidic and polar, with glutamine, which is neutral and polar, at codon 105 of the TCAP protein (p.Glu105Gln). This variant is present in population databases (rs146906267, gnomAD 0.08%), and has an allele count higher than expected for a pathogenic variant. This missense change has been observed in individual(s) with dilated cardiomyopathy and hypertrophic cardiomyopathy (PMID: 24037902, 26332198, 30871747, 31303467). ClinVar contains an entry for this variant (Variation ID: 191776). 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. 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. -
Autosomal recessive limb-girdle muscular dystrophy type 2G Uncertain:1
This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
Cardiomyopathy Benign:1
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Brugada syndrome Benign:1
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Cardiovascular phenotype Benign:1
This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at