GENE REFERENCE / HGNC:12012

TPM3

tropomyosin 3

protein-coding gene1q21.3Gene information

What does this gene do?

The TPM3 gene provides instructions for making a protein called slow muscle alpha (α)-tropomyosin, which is part of the tropomyosin protein family. Tropomyosin proteins regulate the tensing of muscle fibers (muscle contraction) by controlling the binding of two muscle proteins, myosin and actin. In non-muscle cells, tropomyosin proteins play a role in controlling cell shape.

Slow muscle α-tropomyosin is found in skeletal muscles, which are the muscles used for movement. Skeletal muscle is made up of two types of muscle fibers: type I (slow twitch fibers) and type II (fast twitch fibers). Slow muscle α-tropomyosin is found only in type I fibers. Type I fibers are the primary component of skeletal muscles that are resistant to fatigue. For example, muscles involved in posture, such as the neck muscles that hold the head steady, are made predominantly of type I fibers. Slow muscle α-tropomyosin helps regulate muscle contraction in type I skeletal muscle fibers.

Source: MedlinePlus, National Library of Medicine. Source publication: 2023-05-04. Source review: 2012-04.

ClinGen reviews

ClinGen reviews the evidence linking a particular gene to a condition. Each rating below describes the strength of that link. It does not classify a variant in your DNA file.

Condition	Inheritance	Evidence
TPM3-related myopathyMONDO:0100108 · Evaluated 2024-04-08	Autosomal dominant	DefinitiveCongenital Myopathies and Myasthenic Syndromes Gene Curation Expert Panel
TPM3-related myopathyMONDO:0100108 · Evaluated 2024-04-08	Autosomal recessive	DefinitiveCongenital Myopathies and Myasthenic Syndromes Gene Curation Expert Panel

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles: 468
Submissions for variants in or overlapping this gene: 746
Submissions explicitly reporting this gene: 713
Alleles reported pathogenic / likely pathogenic: 42
VariationIDs with uncertain significance: 227
VariationIDs with conflicting classifications: 17

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about TPM3?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 42 alleles in TPM3 reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in TPM3.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

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