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Genetics Home Reference: your guide to understanding genetic conditions
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TPM2

Reviewed June 2015

What is the official name of the TPM2 gene?

The official name of this gene is “tropomyosin 2 (beta).”

TPM2 is the gene's official symbol. The TPM2 gene is also known by other names, listed below.

What is the normal function of the TPM2 gene?

The TPM2 gene provides instructions for making a protein called beta (β)-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.

β-tropomyosin is found primarily in skeletal muscles, which are the muscles used for movement. This protein helps regulate muscle contraction by interacting with other muscle proteins, particularly myosin and actin. These interactions are essential for stabilizing and maintaining structures called sarcomeres within muscle cells. Sarcomeres are the basic units of muscle contraction; they are made of proteins that generate the mechanical force needed for muscles to contract.

How are changes in the TPM2 gene related to health conditions?

cap myopathy - caused by mutations in the TPM2 gene

At least three TPM2 gene mutations have been identified in people with cap myopathy, a disorder that leads to muscle weakness (myopathy) and poor muscle tone (hypotonia). These mutations delete or duplicate genetic material in the TPM2 gene or replace single protein building blocks (amino acids) in the β-tropomyosin protein sequence. The specific effects of these TPM2 gene mutations are unclear, but researchers suggest they may interfere with normal actin-myosin binding, impairing muscle contraction and resulting in the muscle weakness that occurs in cap myopathy.

distal arthrogryposis type 1 - caused by mutations in the TPM2 gene

At least three mutations in the TPM2 gene have been found to cause distal arthrogryposis type 1, a disorder characterized by joint deformities (contractures) in the hands and feet. It is unclear how these mutations lead to contractures in people with distal arthrogryposis type 1, or why the joint problems are typically limited to the hands and feet. However, researchers speculate that contractures may be related to problems with muscle contraction that limit the movement of joints before birth.

Sheldon-Hall syndrome - associated with the TPM2 gene

At least six TPM2 gene mutations have been identified in people with Sheldon-Hall syndrome, a muscle and skeletal disorder similar to distal arthrogryposis type 1 (described above) that impairs joint movement in the hands and feet. Mutations in the TPM2 gene may alter the structure of β-tropomyosin and disrupt the protein's normal function in controlling muscle contractions, resulting in the contractures and other muscle and skeletal abnormalities associated with this condition.

Where is the TPM2 gene located?

Cytogenetic Location: 9p13

Molecular Location on chromosome 9: base pairs 35,681,992 to 35,690,055

The TPM2 gene is located on the short (p) arm of chromosome 9 at position 13.

The TPM2 gene is located on the short (p) arm of chromosome 9 at position 13.

More precisely, the TPM2 gene is located from base pair 35,681,992 to base pair 35,690,055 on chromosome 9.

See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about TPM2?

You and your healthcare professional may find the following resources about TPM2 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the TPM2 gene or gene products?

  • beta-tropomyosin
  • NEM4
  • TMSB
  • TPM2_HUMAN
  • tropomyosin-2
  • tropomyosin beta chain
  • tropomyosin, skeletal muscle beta

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What glossary definitions help with understanding TPM2?

acids ; actin ; arthrogryposis ; cell ; contraction ; distal ; gene ; hypotonia ; joint ; muscle cells ; muscle tone ; myosin ; protein ; protein sequence ; skeletal muscle ; syndrome

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

References

  • Beck AE, McMillin MJ, Gildersleeve HI, Kezele PR, Shively KM, Carey JC, Regnier M, Bamshad MJ. Spectrum of mutations that cause distal arthrogryposis types 1 and 2B. Am J Med Genet A. 2013 Mar;161A(3):550-5. doi: 10.1002/ajmg.a.35809. Epub 2013 Feb 7. (http://www.ncbi.nlm.nih.gov/pubmed/23401156?dopt=Abstract)
  • Clarke NF, Domazetovska A, Waddell L, Kornberg A, McLean C, North KN. Cap disease due to mutation of the beta-tropomyosin gene (TPM2). Neuromuscul Disord. 2009 May;19(5):348-51. doi: 10.1016/j.nmd.2009.03.003. Epub 2009 Apr 3. (http://www.ncbi.nlm.nih.gov/pubmed/19345583?dopt=Abstract)
  • Donner K, Ollikainen M, Ridanpää M, Christen HJ, Goebel HH, de Visser M, Pelin K, Wallgren-Pettersson C. Mutations in the beta-tropomyosin (TPM2) gene--a rare cause of nemaline myopathy. Neuromuscul Disord. 2002 Feb;12(2):151-8. (http://www.ncbi.nlm.nih.gov/pubmed/11738357?dopt=Abstract)
  • Goebel HH. Cap disease uncapped. Neuromuscul Disord. 2007 Jun;17(6):429-32. Epub 2007 Apr 16. (http://www.ncbi.nlm.nih.gov/pubmed/17434306?dopt=Abstract)
  • Lehtokari VL, Ceuterick-de Groote C, de Jonghe P, Marttila M, Laing NG, Pelin K, Wallgren-Pettersson C. Cap disease caused by heterozygous deletion of the beta-tropomyosin gene TPM2. Neuromuscul Disord. 2007 Jun;17(6):433-42. Epub 2007 Apr 16. (http://www.ncbi.nlm.nih.gov/pubmed/17434307?dopt=Abstract)
  • Marttila M, Lemola E, Wallefeld W, Memo M, Donner K, Laing NG, Marston S, Grönholm M, Wallgren-Pettersson C. Abnormal actin binding of aberrant β-tropomyosins is a molecular cause of muscle weakness in TPM2-related nemaline and cap myopathy. Biochem J. 2012 Feb 15;442(1):231-9. doi: 10.1042/BJ20111030. (http://www.ncbi.nlm.nih.gov/pubmed/22084935?dopt=Abstract)
  • Monnier N, Lunardi J, Marty I, Mezin P, Labarre-Vila A, Dieterich K, Jouk PS. Absence of beta-tropomyosin is a new cause of Escobar syndrome associated with nemaline myopathy. Neuromuscul Disord. 2009 Feb;19(2):118-23. doi: 10.1016/j.nmd.2008.11.009. Epub 2009 Jan 19. (http://www.ncbi.nlm.nih.gov/pubmed/19155175?dopt=Abstract)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/7169)
  • Ochala J. Thin filament proteins mutations associated with skeletal myopathies: defective regulation of muscle contraction. J Mol Med (Berl). 2008 Nov;86(11):1197-204. doi: 10.1007/s00109-008-0380-9. Epub 2008 Jun 24. Review. (http://www.ncbi.nlm.nih.gov/pubmed/18574571?dopt=Abstract)
  • Ohlsson M, Quijano-Roy S, Darin N, Brochier G, Lacène E, Avila-Smirnow D, Fardeau M, Oldfors A, Tajsharghi H. New morphologic and genetic findings in cap disease associated with beta-tropomyosin (TPM2) mutations. Neurology. 2008 Dec 2;71(23):1896-901. doi: 10.1212/01.wnl.0000336654.44814.b8. (http://www.ncbi.nlm.nih.gov/pubmed/19047562?dopt=Abstract)
  • Sung SS, Brassington AM, Grannatt K, Rutherford A, Whitby FG, Krakowiak PA, Jorde LB, Carey JC, Bamshad M. Mutations in genes encoding fast-twitch contractile proteins cause distal arthrogryposis syndromes. Am J Hum Genet. 2003 Mar;72(3):681-90. (http://www.ncbi.nlm.nih.gov/pubmed/12592607?dopt=Abstract)
  • Tajsharghi H, Kimber E, Holmgren D, Tulinius M, Oldfors A. Distal arthrogryposis and muscle weakness associated with a beta-tropomyosin mutation. Neurology. 2007 Mar 6;68(10):772-5. (http://www.ncbi.nlm.nih.gov/pubmed/17339586?dopt=Abstract)
  • Tajsharghi H, Ohlsson M, Lindberg C, Oldfors A. Congenital myopathy with nemaline rods and cap structures caused by a mutation in the beta-tropomyosin gene (TPM2). Arch Neurol. 2007 Sep;64(9):1334-8. (http://www.ncbi.nlm.nih.gov/pubmed/17846275?dopt=Abstract)

 

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: June 2015
Published: July 19, 2015