rs199474714

Variant names:

• chr1-154173113-C-T
• rs199474714
• NM_152263.4:c.466G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PM2 PP2 PP3

The NM_152263.4(TPM3):​c.466G>A​(p.Ala156Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: TPM3 NM_152263.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1 O:1
• Conservation: PhyloP100: 7.85
• Publications: 9 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: Likely_pathogenic. The variant received 6 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_152263.4
• 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.84

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TPM3	NM_152263.4	c.466G>A	p.Ala156Thr	missense_variant	Exon 4 of 10	ENST00000651641.1	NP_689476.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TPM3	ENST00000651641.1	c.466G>A	p.Ala156Thr	missense_variant	Exon 4 of 10		NM_152263.4	ENSP00000498577.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Jan 03, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine with threonine at codon 156 of the TPM3 protein (p.Ala156Thr). The alanine residue is highly conserved and there is a small physicochemical difference between alanine and threonine. This variant is not present in population databases (ExAC no frequency). This variant has been observed in a family affected with nemaline myopathy (PMID: 20012312). ClinVar contains an entry for this variant (Variation ID: 140498). This variant has been reported to affect TPM3 protein function (PMID:22749829). 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 provided Other:1

-

TPM3 homepage - Leiden Muscular Dystrophy pages

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	32
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.49	T;.;.;D;.;.;.;.;.;.;D
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.88	D;D;D;D;.;D;D;D;D;D;D
M_CAP	Uncertain	0.25	D
MetaRNN	Pathogenic	0.84	D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.0	.;.;.;.;.;.;.;.;.;.;H
PhyloP100		7.8
PrimateAI	Pathogenic	0.85	D
PROVEAN	Uncertain	-3.7	.;D;D;D;.;D;D;D;D;D;D
REVEL	Pathogenic	0.92
Sift	Uncertain	0.019	.;D;D;D;.;D;D;D;D;D;D
Sift4G	Uncertain	0.015	D;D;D;D;D;D;D;D;D;D;D
Polyphen		0.98, 0.91	.;D;.;.;.;.;.;.;P;.;.
Vest4		0.67
MVP		0.98
MPC		2.1
ClinPred		0.99	D
GERP RS		5.9
RBP_binding_hub_radar		0.92
RBP_regulation_power_radar		2.6
Varity_R		0.63
Mutation Taster		=0/100	disease causing

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: rs199474714; hg19: chr1-154145589; COSMIC: COSV55136634; COSMIC: COSV55136634;