rs149659674

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 5P and 5B. PM1PM5PP2BP4BS2

The NM_001018005.2(TPM1):c.829G>A(p.Ala277Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000167 in 1,613,872 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 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. A277V) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000085 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000096 ( 0 hom. )

Consequence

TPM1
NM_001018005.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:7

Conservation

PhyloP100: 10.0

Variant links:

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]

TPM1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 0 ACMG points.

PM1

In a chain Tropomyosin alpha-1 chain (size 283) in uniprot entity TPM1_HUMAN there are 61 pathogenic changes around while only 1 benign (98%) in NM_001018005.2

PM5

Other missense variant is known to change same aminoacid residue: Variant chr15-63064121-C-T is described in Lovd as [Likely_pathogenic].

PP2

Missense variant in the TPM1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 42 curated pathogenic missense variants (we use a threshold of 10). The gene has 25 curated benign missense variants. Gene score misZ: 2.8677 (below the threshold of 3.09). Trascript score misZ: 3.9402 (above the threshold of 3.09). GenCC associations: The gene is linked to dilated cardiomyopathy, left ventricular noncompaction, hypertrophic cardiomyopathy, hypertrophic cardiomyopathy 3, arrhythmogenic right ventricular cardiomyopathy, familial isolated dilated cardiomyopathy, dilated cardiomyopathy 1Y.

BP4

Computational evidence support a benign effect (MetaRNN=0.27957192).

BS2

High AC in GnomAd4 at 13 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TPM1	NM_001018005.2 link	c.829G>A	p.Ala277Thr	missense_variant	Exon 9 of 10	ENST00000403994.9	NP_001018005.1	P09493-1D9YZV4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TPM1	ENST00000403994.9 link	c.829G>A	p.Ala277Thr	missense_variant	Exon 9 of 10	1	NM_001018005.2	ENSP00000385107.4		P09493-1

Frequencies

GnomAD3 genomes

AF:

0.0000854

AC:

AN:

152160

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000290

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000199

AC:

AN:

251036

Hom.:

AF XY:

0.0000147

AC XY:

AN XY:

135696

show subpopulations

Gnomad AFR exome

AF:

0.000123

Gnomad AMR exome

AF:

0.0000868

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000958

AC:

AN:

1461712

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727148

show subpopulations

Gnomad4 AFR exome

AF:

0.000209

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000180

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000854

AC:

AN:

152160

Hom.:

Cov.:

AF XY:

0.000121

AC XY:

AN XY:

74336

show subpopulations

Gnomad4 AFR

AF:

0.000290

Gnomad4 AMR

AF:

0.0000655

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000987

Hom.:

Bravo

AF:

0.000106

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000330

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Hypertrophic cardiomyopathy

Uncertain:2

Nov 20, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces alanine with threonine at codon 277 of the TPM1 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in individuals affected with hypertrophic cardiomyopathy (PMID: 27532257) and dilated cardiomyopathy (PMID: 32880476). This variant has been identified in 8/282436 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Jan 23, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 277 of the TPM1 protein (p.Ala277Thr). This variant is present in population databases (rs149659674, gnomAD 0.02%). This missense change has been observed in individual(s) with dilated cardiomyopathy, hypertrophic cardiomyopathy (PMID: 32880476, 37652022). ClinVar contains an entry for this variant (Variation ID: 43442). 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 tolerated. 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. -

not specified

Uncertain:1

Oct 31, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant classified as Uncertain Significance - Favor Benign. The Ala277Thr varia nt in TPM1 has not been reported in the literature. This variant has been identi fied in 2 Black individuals with HCM tested by our laboratory (including this in dividual) and has been identified in 1/4406 African American chromosomes from a broad population by the NHLBI Exome Sequencing Project (http://evs.gs.washington .edu/EVS; dbSNP rs149659674). Alanine (Ala) at position 277 is not well conserve d in evolution with several species carrying the mutant amino acid (threonine). This suggests that this variant is tolerated but is insufficient to rule out a role in disease. Additional information is needed to fully assess the clinical s ignificance of the Ala277Thr variant. -

Cardiomyopathy

Uncertain:1

Sep 28, 2023

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

not provided

Uncertain:1

Jun 28, 2024

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In silico analysis indicates that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 34699384, 34194005, 32880476) -

Hypertrophic cardiomyopathy 3;C2678476:Dilated cardiomyopathy 1Y

Uncertain:1

Sep 03, 2021

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cardiovascular phenotype

Uncertain:1

Aug 26, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.A277T variant (also known as c.829G>A), located in coding exon 9 of the TPM1 gene, results from a G to A substitution at nucleotide position 829. The alanine at codon 277 is replaced by threonine, an amino acid with similar properties. This variant has been reported in hypertrophic and dilated cardiomyopathy cohorts, but clinical details were limited (Alfares AA et al. Genet Med, 2015 Nov;17:880-8; Stroeks SLVM et al. Genet Med, 2021 Nov;23:2186-2193). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.41

CardioboostCm

Benign

0.014

BayesDel_addAF

Pathogenic

0.17

BayesDel_noAF

Pathogenic

0.25

CADD

Uncertain

DANN

Benign

0.46

DEOGEN2

Uncertain

0.66

.;D;.;.;.;T

Eigen

Benign

-0.22

Eigen_PC

Benign

0.10

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Uncertain

0.95

D;D;D;D;D;D

M_CAP

Uncertain

0.19

MetaRNN

Benign

0.28

T;T;T;T;T;T

MetaSVM

Uncertain

0.014

MutationAssessor

Benign

-0.92

N;N;N;.;.;.

PROVEAN

Benign

1.0

N;N;.;.;.;N

REVEL

Uncertain

0.45

Sift

Benign

1.0

T;T;.;.;.;T

Sift4G

Benign

1.0

T;T;.;.;.;T

Polyphen

0.0, 0.0010

.;B;B;.;.;.

Vest4

0.77

MVP

0.98

ClinPred

0.15

GERP RS

5.8

Varity_R

0.37

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over