1-154167941-C-T

Position:

• chr1-154167941-C-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_152263.4(TPM3):​c.855-1G>A variant causes a splice acceptor change. The variant allele was found at a frequency of 0.0000041 in 1,461,798 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: TPM3 NM_152263.4 splice_acceptor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts P:1 U:2 O:1
• Conservation: PhyloP100: 3.62

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]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease,
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TPM3	NM_152263.4	c.855-1G>A		splice_acceptor_variant		ENST00000651641.1	NP_689476.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TPM3	ENST00000651641.1	c.855-1G>A		splice_acceptor_variant			NM_152263.4	ENSP00000498577	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000202 AC: 5 AN: 247088 Hom.: 0 AF XY: 0.0000223 AC XY: 3 AN XY: 134284

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000145

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: 0.00000410 AC: 6 AN: 1461798 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727206

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000134

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.0000227

ExAC AF: 0.00000828 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1 Other:1

not provided, no classification provided	literature only	TPM3 homepage - Leiden Muscular Dystrophy pages	-	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Mar 25, 2022	- -

Congenital myopathy 4B, autosomal recessive Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Aug 27, 2002

- -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 06, 2022

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. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant is associated with altered splicing resulting in multiple RNA products (PMID: 12196661). ClinVar contains an entry for this variant (Variation ID: 12448). This variant has been observed in individual(s) with autosomal recessive congenital myopathy (PMID: 12196661). This variant is present in population databases (rs113605263, gnomAD 0.01%). This sequence change falls in intron 9 of the TPM3 gene. It does not directly change the encoded amino acid sequence of the TPM3 protein. It affects a nucleotide within the consensus splice site. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.17	D
BayesDel_noAF	Pathogenic	0.25
CADD	Pathogenic	32
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Uncertain	0.94	D
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D
GERP RS		5.4

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.28		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.28		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs113605263; hg19: chr1-154140417;