rs397516389

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_001018005.2(TPM1):​c.775G>A​(p.Glu259Lys) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,666 control chromosomes in the GnomAD database, with no homozygous occurrence. 1/1 splice prediction tools predict no significant impact on normal splicing. 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. E259Q) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 33)
Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

TPM1
NM_001018005.2 missense, splice_region

Scores

2
6
11

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 10.0

Publications

1 publications found
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 Gene-Disease associations (from GenCC):
  • hypertrophic cardiomyopathy
    Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
  • hypertrophic cardiomyopathy 3
    Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia, G2P
  • dilated cardiomyopathy 1Y
    Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
  • dilated cardiomyopathy
    Inheritance: AD Classification: MODERATE Submitted by: ClinGen
  • familial isolated dilated cardiomyopathy
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • left ventricular noncompaction
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • arrhythmogenic right ventricular cardiomyopathy
    Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2
Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TPM1NM_001018005.2 linkc.775G>A p.Glu259Lys missense_variant, splice_region_variant Exon 9 of 10 ENST00000403994.9 NP_001018005.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TPM1ENST00000403994.9 linkc.775G>A p.Glu259Lys missense_variant, splice_region_variant Exon 9 of 10 1 NM_001018005.2 ENSP00000385107.4

Frequencies

GnomAD3 genomes
Cov.:
33
GnomAD2 exomes
AF:
0.00000398
AC:
1
AN:
251014
AF XY:
0.00000737
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000880
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000137
AC:
2
AN:
1461666
Hom.:
0
Cov.:
31
AF XY:
0.00000275
AC XY:
2
AN XY:
727138
show subpopulations
⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
33478
American (AMR)
AF:
0.00
AC:
0
AN:
44720
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86228
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53272
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00000180
AC:
2
AN:
1111974
Other (OTH)
AF:
0.00
AC:
0
AN:
60390
⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0385499), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.375
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
Cov.:
33
ExAC
AF:
0.00000824
AC:
1

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:3
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Hypertrophic cardiomyopathy Uncertain:2
Sep 24, 2021
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces glutamic acid with lysine at codon 259 of the TPM1 protein (p.Glu259Lys). The glutamic acid residue is weakly conserved and there is a small physicochemical difference between glutamic acid and lysine. This variant is present in population databases (rs397516389, ExAC 0.002%). This variant has not been reported in the literature in individuals with TPM1-related conditions. ClinVar contains an entry for this variant (Variation ID: 43440). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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. -

Sep 23, 2024
All of Us Research Program, National Institutes of Health
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not specified Uncertain:1
May 24, 2012
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The Glu259Lys variant in TPM1 has not been reported in the literature nor previo usly identified by our laboratory. Computational analyses (conservation, AlignGV GD, PolyPhen2, and SIFT) are limited/unavailable for this variant due to the pre sent of alternative transcript in TPM1. In summary, additional information is ne eded to fully assess the clinical significance of the Glu259Lys variant. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.59
CardioboostCm
Benign
0.029
BayesDel_addAF
Pathogenic
0.22
D
BayesDel_noAF
Uncertain
0.080
CADD
Pathogenic
27
DANN
Benign
0.90
DEOGEN2
Uncertain
0.65
.;D;.;.;.;D
Eigen
Benign
-0.35
Eigen_PC
Benign
-0.15
FATHMM_MKL
Uncertain
0.97
D
LIST_S2
Uncertain
0.87
D;D;D;D;D;D
M_CAP
Benign
0.026
D
MetaRNN
Uncertain
0.45
T;T;T;T;T;T
MetaSVM
Benign
-0.73
T
MutationAssessor
Benign
0.070
N;N;N;.;.;.
PhyloP100
10
PROVEAN
Benign
-0.82
N;N;.;.;.;N
REVEL
Uncertain
0.44
Sift
Benign
0.73
T;T;.;.;.;T
Sift4G
Benign
0.42
T;T;.;.;.;T
Polyphen
0.0
.;B;B;.;.;.
Vest4
0.82
MutPred
0.71
Gain of ubiquitination at E259 (P = 0.017);Gain of ubiquitination at E259 (P = 0.017);Gain of ubiquitination at E259 (P = 0.017);Gain of ubiquitination at E259 (P = 0.017);.;.;
MVP
0.96
ClinPred
0.30
T
GERP RS
4.9
Varity_R
0.37
Mutation Taster
=76/24
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.030
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs397516389; hg19: chr15-63356265; API