chr15-63062219-C-T
Variant summary
Our verdict is Pathogenic. Variant got 15 ACMG points: 15P and 0B. PM1PM2PP2PP3_ModeratePP5_Very_Strong
The NM_001018005.2(TPM1):c.644C>T(p.Ser215Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,613,842 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).
Frequency
Consequence
NM_001018005.2 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 15 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152094Hom.: 0 Cov.: 33
GnomAD3 exomes AF: 0.00000398 AC: 1AN: 251270Hom.: 0 AF XY: 0.00000736 AC XY: 1AN XY: 135792
GnomAD4 exome AF: 6.84e-7 AC: 1AN: 1461748Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0AN XY: 727182
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152094Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0AN XY: 74270
ClinVar
Submissions by phenotype
not provided Pathogenic:2Other:1
Not observed at significant frequency in large population cohorts (gnomAD); Published in vitro functional studies demonstrated that p.(S215L) caused significantly reduced actin binding and increased calcium sensitivity, thus affecting the contractile properties of the tropomyosin protein (PMID: 25548289, 36896133); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 18403758, 23204897, 23700264, 26936621, 27600940, 25607779, 27532257, 29121657, 25548289, 31737537, 33673806, 36896133, 38958565, 37652022, 34011823, 36158814) -
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Cardiomyopathy Pathogenic:2
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Hypertrophic cardiomyopathy Pathogenic:2
The p.Ser215Leu variant in TPM1 has been reported in at least 7 individuals with HCM and segregated with disease in 6 individuals from 3 families (Morita 2008 PMID: 18403758, Rangaraju 2012 PMID: 23204897, Selvi Rani 2015 PMID: 25607779, Cecconi 2016 PMID: 27600940, Walsh 2017 PMID: 27532257, Viswanathan 2017 PMID: 29121657, Bales 2016 PMID: 26936621). In at least three families with early onset disease, this variant was identified in conjunction with a second pathogenic variant associated to cardiomyopathy, and one individual had cardiomyopathy while only harboring the second variant and not the p.Ser215Leu variant. This variant has also been reported by other clinical laboratories in ClinVar (Variation ID 31883) and has also been identified in 0.0009% (1/113564) of European chromosomes by gnomAD (https://gnomad.broadinstitute.org/). In vitro functional studies provide some evidence that this variant impacts protein function (Gupte 2015 PMID: 25548289); and computational prediction tools and conservation analyses suggest that this variant may impact the protein. In summary, although additional studies are required to fully establish its clinical significance, this variant meets criteria to be classified as likely pathogenic for autosomal dominant hypertrophic cardiomyopathy. ACMG/AMP Criteria applied: PM2_supporting, PS4_Moderate, PP3, PS3_Supporting, PP1_Moderate. -
This sequence change replaces serine, which is neutral and polar, with leucine, which is neutral and non-polar, at codon 215 of the TPM1 protein (p.Ser215Leu). This variant is present in population databases (rs199476316, gnomAD 0.0009%). This missense change has been observed in individuals with hypertrophic cardiomyopathy (HCM) (PMID: 18403758, 23204897, 25607779, 27600940). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 31883). 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. Experimental studies have shown that this missense change affects TPM1 function (PMID: 23700264, 25548289). For these reasons, this variant has been classified as Pathogenic. -
Dilated cardiomyopathy 1Y Pathogenic:1
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Primary familial hypertrophic cardiomyopathy Pathogenic:1
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Cardiovascular phenotype Pathogenic:1
The p.S215L pathogenic mutation (also known as c.644C>T), located in coding exon 7 of the TPM1 gene, results from a C to T substitution at nucleotide position 644. The serine at codon 215 is replaced by leucine, an amino acid with dissimilar properties. This variant has been reported in multiple individuals with hypertrophic cardiomyopathy, and has been found to co-segregate with disease (Morita H et al. N. Engl. J. Med. 2008;358:1899-908, Rangaraju A et al. Exp Clin. Cardiol. 2012;17:26-9, Selvi Rani D et al. DNA Cell Biol. 2015;34:350-9, Bales ND et al. Pediatr. Cardiol. 2016;37:845-51). Patients who harbored this variant in the compound heterozygous state were noted to be more severely affected (Selvi Rani D et al. DNA Cell Biol. 2015;34:350-9). In an assay testing TPM1 function, this variant showed a functionally abnormal result (Gupte TM et al. J. Biol. Chem. 2015;290:7003-15). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at