rs730881146
Variant summary
Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1_StrongPM2PP3_Strong
The NM_001018005.2(TPM1):c.240+1G>A variant causes a splice donor change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 2/2 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).
Frequency
Genomes: not found (cov: 32)
Consequence
TPM1
NM_001018005.2 splice_donor
NM_001018005.2 splice_donor
Scores
5
1
1
Splicing: ADA: 1.000
2
Clinical Significance
Conservation
PhyloP100: 9.60
Genes affected
TPM1 (HGNC:12010): (tropomyosin 1) This gene is a member of the tropomyosin family of highly conserved, widely distributed actin-binding proteins involved in the contractile system of striated and smooth muscles and the cytoskeleton of non-muscle cells. Tropomyosin is composed of two alpha-helical chains arranged as a coiled-coil. It is polymerized end to end along the two grooves of actin filaments and provides stability to the filaments. The encoded protein is one type of alpha helical chain that forms the predominant tropomyosin of striated muscle, where it also functions in association with the troponin complex to regulate the calcium-dependent interaction of actin and myosin during muscle contraction. In smooth muscle and non-muscle cells, alternatively spliced transcript variants encoding a range of isoforms have been described. Mutations in this gene are associated with type 3 familial hypertrophic cardiomyopathy and dilated cardiomyopathy 1Y. [provided by RefSeq, Jun 2022]
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ACMG classification
Classification made for transcript
Verdict is Pathogenic. Variant got 10 ACMG points.
PVS1
?
Splicing variant, NOT destroyed by nmd, known LOF gene, truncates exone, which is 0.14619882 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
PM2
?
Very rare variant in population databases, with high coverage;
PP3
?
Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. No scorers claiming Benign.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
---|---|---|---|---|---|---|---|
TPM1 | NM_001018005.2 | c.240+1G>A | splice_donor_variant | ENST00000403994.9 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
TPM1 | ENST00000403994.9 | c.240+1G>A | splice_donor_variant | 1 | NM_001018005.2 | A1 |
Frequencies
GnomAD3 genomes ? Cov.: 32
GnomAD3 genomes
?
Cov.:
32
GnomAD4 exome Cov.: 33
GnomAD4 exome
Cov.:
33
GnomAD4 genome ? Cov.: 32
GnomAD4 genome
?
Cov.:
32
ClinVar
Significance: Uncertain significance
Submissions summary: Uncertain:4
Revision: criteria provided, multiple submitters, no conflicts
LINK: link
Submissions by phenotype
not specified Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine | Feb 12, 2015 | Variant classified as Uncertain Significance - Favor Pathogenic. The c.240+1G>A variant in TPM1 has not been previously reported in individuals with cardiomyopa thy and was absent from large population studies. This variant occurs in the inv ariant region (+/- 1,2) of the splice consensus sequence and is predicted to cau se altered splicing leading to an abnormal or absent protein. Despite the severi ty of the predicted impact it is unclear if this change causes disease because t his type of variant is very rare in this gene. In summary, while there is some s uspicion for a pathogenic role, the clinical significance of the c.240+1G>A vari ant is uncertain. - |
not provided Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | GeneDx | Sep 20, 2022 | Not observed at significant frequency in large population cohorts (gnomAD); Canonical splice site variant with an unclear effect on protein function; Has not been previously published as pathogenic or benign to our knowledge - |
Hypertrophic cardiomyopathy Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Invitae | Aug 07, 2021 | This variant is not present in population databases (ExAC no frequency). 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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 181673). This variant has not been reported in the literature in individuals affected with TPM1-related conditions. This sequence change affects a donor splice site in intron 2 of the TPM1 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), however the current clinical and genetic evidence is not sufficient to establish whether loss-of-function variants in TPM1 cause disease. - |
Cardiovascular phenotype Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Ambry Genetics | Sep 09, 2019 | The c.240+1G>A intronic variant results from a G to A substitution one nucleotide after coding exon 2 of the TPM1 gene. This nucleotide position is highly conserved in available vertebrate species. Using the BDGP and ESEfinder splice site prediction tools, this alteration is predicted to abolish the native splice donor site; however, direct evidence is unavailable. Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. However, loss of function of TPM1 has not been clearly established as a mechanism of disease. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. - |
Computational scores
Source:
Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
D
BayesDel_noAF
Pathogenic
Cadd
Pathogenic
Dann
Uncertain
Eigen
Pathogenic
Eigen_PC
Pathogenic
FATHMM_MKL
Pathogenic
D
MutationTaster
Benign
D;D;D;D;D;D;D;D
GERP RS
Splicing
Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
dbscSNV1_RF
Pathogenic
SpliceAI score (max)
Details are displayed if max score is > 0.2
DS_DL_spliceai
Position offset: -1
Find out detailed SpliceAI scores and Pangolin per-transcript scores at