rs1553248513

Variant names:

• chr1-154170415-T-C
• rs1553248513
• NM_152263.4:c.760A>G

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_152263.4(TPM3):​c.760A>G​(p.Ile254Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,880 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. I254T) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: TPM3 NM_152263.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.98
• Publications: 0 publications found

Genes affected

TPM3 (HGNC:12012): (tropomyosin 3) This gene encodes a member of the tropomyosin family of actin-binding proteins. Tropomyosins are dimers of coiled-coil proteins that provide stability to actin filaments and regulate access of other actin-binding proteins. Mutations in this gene result in autosomal dominant nemaline myopathy and other muscle disorders. This locus is involved in translocations with other loci, including anaplastic lymphoma receptor tyrosine kinase (ALK) and neurotrophic tyrosine kinase receptor type 1 (NTRK1), which result in the formation of fusion proteins that act as oncogenes. There are numerous pseudogenes for this gene on different chromosomes. Alternative splicing results in multiple transcript variants. [provided by RefSeq, May 2013]

TPM3 Gene-Disease associations (from GenCC):

• congenital myopathy 4A, autosomal dominant

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• TPM3-related myopathy

  Inheritance: SD Classification: DEFINITIVE Submitted by: ClinGen
• congenital myopathy 4B, autosomal recessive

  Inheritance: SD, AR Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• congenital fiber-type disproportion myopathy

  Inheritance: SD, AD Classification: MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet
• cap myopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• childhood-onset nemaline myopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• congenital generalized hypercontractile muscle stiffness syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• intermediate nemaline myopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

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

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the TPM3 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 19 curated pathogenic missense variants (we use a threshold of 10). The gene has 2 curated benign missense variants. Gene score misZ: 2.3546 (below the threshold of 3.09). Trascript score misZ: 3.2484 (above the threshold of 3.09). GenCC associations: The gene is linked to congenital myopathy 4A, autosomal dominant, intermediate nemaline myopathy, congenital fiber-type disproportion myopathy, TPM3-related myopathy, congenital myopathy 4B, autosomal recessive, childhood-onset nemaline myopathy, cap myopathy, congenital generalized hypercontractile muscle stiffness syndrome.
• BP4: Computational evidence support a benign effect (MetaRNN=0.34073615).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TPM3	NM_152263.4	c.760A>G	p.Ile254Val	missense_variant	Exon 8 of 10	ENST00000651641.1	NP_689476.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TPM3	ENST00000651641.1	c.760A>G	p.Ile254Val	missense_variant	Exon 8 of 10		NM_152263.4	ENSP00000498577.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461880 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727242

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1112008

Other (OTH) AF: 0.0000166 AC: 1 AN: 60396

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital myopathy with fiber type disproportion;C5829889:Congenital myopathy 4B, autosomal recessive Uncertain:1

Jul 26, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C25"). ClinVar contains an entry for this variant (Variation ID: 531179). This variant has not been reported in the literature in individuals affected with TPM3-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 254 of the TPM3 protein (p.Ile254Val). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Uncertain	0.11
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.24	T;.;.;D;.;.;.;.;.;.;D
Eigen	Benign	0.13
Eigen_PC	Uncertain	0.25
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.86	D;T;D;D;.;D;T;D;T;T;D
M_CAP	Benign	0.023	T
MetaRNN	Benign	0.34	T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Pathogenic	0.80	D
MutationAssessor	Benign	1.9	.;.;.;.;.;.;.;.;.;.;L
PhyloP100		8.0
PrimateAI	Pathogenic	0.82	D
PROVEAN	Benign	-0.67	.;N;N;N;.;N;N;N;N;N;N
REVEL	Uncertain	0.58
Sift	Uncertain	0.0080	.;D;D;D;.;D;D;D;D;D;T
Sift4G	Benign	0.60	T;T;T;T;T;T;T;T;T;T;T
Polyphen		0.20, 0.077	.;B;.;.;.;.;.;.;B;.;.
Vest4		0.44
MVP		0.89
MPC		0.96
ClinPred		0.63	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.8
Varity_R		0.15
Mutation Taster		=59/41	polymorphism

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

Other links and lift over

dbSNP: rs1553248513; hg19: chr1-154142891;