NM_001018005.2:c.253G>A

Variant names:

• chr15-63056997-G-A
• rs730881156
• NM_001018005.2:c.253G>A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 5P and 4B. PM1 PP2 PP3_Moderate BS2

The NM_001018005.2(TPM1):​c.253G>A​(p.Val85Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000041 in 1,461,866 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 Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: TPM1 NM_001018005.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 10.0

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 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
• 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.855
• BS2: High AC in GnomAdExome4 at 6 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TPM1	NM_001018005.2	c.253G>A	p.Val85Ile	missense_variant	Exon 3 of 10	ENST00000403994.9	NP_001018005.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TPM1	ENST00000403994.9	c.253G>A	p.Val85Ile	missense_variant	Exon 3 of 10	1	NM_001018005.2	ENSP00000385107.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000410 AC: 6 AN: 1461866 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727240

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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: 0.00000360

Gnomad4 OTH exome AF: 0.00

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

Submissions by phenotype

Hypertrophic cardiomyopathy Uncertain:2

Aug 10, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is not present in population databases (gnomAD no frequency). This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 85 of the TPM1 protein (p.Val85Ile). This missense change has been observed in individual(s) with hypertrophic cardiomyopathy (PMID: 29121657). ClinVar contains an entry for this variant (Variation ID: 181683). 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. -

Aug 06, 2024

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 valine with isoleucine at codon 85 of the TPM1 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in a familial case of hypertrophic cardiomyopathy with two carriers (PMID: 29121657). This variant has not been identified 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. -

Cardiomyopathy Uncertain:1

Oct 09, 2023

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces valine with isoleucine at codon 85 of the TPM1 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in a familial case of hypertrophic cardiomyopathy with two carriers (PMID: 29121657). This variant has not been identified 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.29
CardioboostCm	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.20
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.80	.;.;D;D;.;.;.;.;.;.;D;.;.;.;D
Eigen	Pathogenic	0.86
Eigen_PC	Pathogenic	0.86
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.96	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Uncertain	0.27	D
MetaRNN	Pathogenic	0.85	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.3	M;M;M;.;M;M;M;M;.;.;.;.;.;.;.
PrimateAI	Uncertain	0.71	T
PROVEAN	Benign	-0.78	N;N;N;N;N;N;N;.;.;N;N;.;N;N;N
REVEL	Uncertain	0.64
Sift	Uncertain	0.0010	D;D;D;D;D;D;D;.;.;D;D;.;D;D;D
Sift4G	Benign	0.14	T;T;T;T;T;T;T;.;.;T;T;.;T;T;T
Polyphen		0.57, 1.0, 0.83, 0.90	.;.;P;D;.;.;.;P;.;.;.;.;.;P;.
Vest4		0.68
MutPred		0.74		.;.;.;Gain of catalytic residue at V127 (P = 0.0907);.;.;.;.;.;.;.;.;.;.;.;
MVP		0.87
MPC		2.2
ClinPred		0.95	D
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.76
gMVP		0.97

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

Other links and lift over

dbSNP: rs730881156; hg19: chr15-63349196;