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URL of this page: https://medlineplus.gov/genetics/gene/tpm2/

TPM2 gene

tropomyosin 2

Normal Function

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.

Health Conditions Related to Genetic Changes

Cap myopathy

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.

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Distal arthrogryposis type 1

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.

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Congenital fiber-type disproportion

MedlinePlus Genetics provides information about Congenital fiber-type disproportion

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Nemaline myopathy

MedlinePlus Genetics provides information about Nemaline myopathy

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Sheldon-Hall syndrome

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.

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Other Names for This Gene

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

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases

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. Citation on PubMed or Free article on PubMed Central
  • 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. Citation on PubMed
  • Donner K, Ollikainen M, Ridanpaa 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. doi: 10.1016/s0960-8966(01)00252-8. Citation on PubMed
  • Goebel HH. Cap disease uncapped. Neuromuscul Disord. 2007 Jun;17(6):429-32. doi: 10.1016/j.nmd.2007.03.011. Epub 2007 Apr 16. No abstract available. Citation on PubMed
  • 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. doi: 10.1016/j.nmd.2007.02.015. Epub 2007 Apr 16. Citation on PubMed
  • Marttila M, Lemola E, Wallefeld W, Memo M, Donner K, Laing NG, Marston S, Gronholm M, Wallgren-Pettersson C. Abnormal actin binding of aberrant beta-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. Citation on PubMed
  • 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. Citation on PubMed
  • 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. Citation on PubMed
  • Ohlsson M, Quijano-Roy S, Darin N, Brochier G, Lacene 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. Citation on PubMed
  • 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. doi: 10.1086/368294. Citation on PubMed or Free article on PubMed Central
  • 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. doi: 10.1212/01.wnl.0000256339.40667.fb. Citation on PubMed
  • 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. doi: 10.1001/archneur.64.9.1334. Citation on PubMed

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.