TOR1A Gene

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This entry is adapted from the peer-reviewed paper https://medlineplus.gov/genetics/gene/tor1a

Torsin family 1 member A: The TOR1A gene (also known as DYT1) provides instructions for making a protein called torsinA.

genes

1. Normal Function

The TOR1A gene (also known as DYT1) provides instructions for making a protein called torsinA. This protein is found in the space between two neighboring structures within cells, the nuclear envelope and the endoplasmic reticulum. The nuclear envelope surrounds the nucleus and separates it from the rest of the cell. The endoplasmic reticulum processes proteins and other molecules and helps transport them to specific destinations either inside or outside the cell. Although little is known about the function of torsinA, studies suggest that it may help process and transport other proteins. TorsinA may also participate in the movement of membranes associated with the nuclear envelope and endoplasmic reticulum.

TorsinA is active in many of the body's tissues, and it is particularly important for the normal function of nerve cells in the brain. For example, researchers have found high levels of torsinA in a part of the brain called the substantia nigra. This region contains nerve cells that produce dopamine, a chemical messenger that transmits signals within the brain to produce smooth physical movements.

2. Health Conditions Related to Genetic Changes

2.1. Early-onset primary dystonia

A particular mutation in the TOR1A gene causes most cases of early-onset primary dystonia. This mutation, which is often called the GAG deletion or delta GAG, deletes three DNA building blocks (base pairs) from the TOR1A gene. The resulting torsinA protein is missing one protein building block (amino acid) in a critical region. The altered protein's effect on the function of nerve cells in the brain is unclear. People with early-onset primary dystonia do not have a loss of nerve cells or obvious changes in the structure of the brain that would explain the abnormal muscle contractions seen with this condition. Instead, the altered torsinA protein may have subtle effects on the connections between nerve cells and likely disrupts chemical signaling between nerve cells that control movement. Researchers are working to determine how a change in this protein leads to the characteristic features of this disorder.

2.2. Benign essential blepharospasm

Several studies have examined a possible relationship between common variations (polymorphisms) in the TOR1A gene and several forms of adult-onset dystonia, including benign essential blepharospasm. The results of these studies have been mixed. Some research has suggested that certain polymorphisms increase a person's risk of developing benign essential blepharospasm. However, other studies have found no connection between changes in the TOR1A gene and risk of this disorder. Researchers are still working to clarify whether variants of the TOR1A gene are related to benign essential blepharospasm and other adult-onset dystonias.

3. Other Names for This Gene

DQ2
Dystonia 1 protein
dystonia 1, torsion (autosomal dominant; torsinA)
DYT1
TOR1A_HUMAN
torsin family 1, member A (torsin A)
Torsin-1A
torsinA

References

Bragg DC, Slater DJ, Breakefield XO. TorsinA and early-onset torsion dystonia.Adv Neurol. 2004;94:87-93. Review.
Breakefield XO, Blood AJ, Li Y, Hallett M, Hanson PI, Standaert DG. Thepathophysiological basis of dystonias. Nat Rev Neurosci. 2008 Mar;9(3):222-34.doi: 10.1038/nrn2337. Review.
Brüggemann N, Kock N, Lohmann K, König IR, Rakovic A, Hagenah J, Schmidt A,Ziegler A, Jabusch HC, Siebner H, Altenmüller E, Münchau A, Klein C. The D216Hvariant in the DYT1 gene: a susceptibility factor for dystonia in familial cases?Neurology. 2009 Apr 21;72(16):1441-3. doi: 10.1212/WNL.0b013e3181a1861e.
Clarimon J, Brancati F, Peckham E, Valente EM, Dallapiccola B, Abruzzese G,Girlanda P, Defazio G, Berardelli A, Hallett M, Singleton AB. Assessing the role of DRD5 and DYT1 in two different case-control series with primary blepharospasm.Mov Disord. 2007 Jan 15;22(2):162-6.
Defazio G, Matarin M, Peckham EL, Martino D, Valente EM, Singleton A, Crawley A, Aniello MS, Brancati F, Abbruzzese G, Girlanda P, Livrea P, Hallett M,Berardelli A. The TOR1A polymorphism rs1182 and the risk of spread in primaryblepharospasm. Mov Disord. 2009 Mar 15;24(4):613-6. doi: 10.1002/mds.22471.
Hewett JW, Tannous B, Niland BP, Nery FC, Zeng J, Li Y, Breakefield XO. MutanttorsinA interferes with protein processing through the secretory pathway in DYT1 dystonia cells. Proc Natl Acad Sci U S A. 2007 Apr 24;104(17):7271-6.
Kabakci K, Hedrich K, Leung JC, Mitterer M, Vieregge P, Lencer R, Hagenah J,Garrels J, Witt K, Klostermann F, Svetel M, Friedman J, Kostic V, Bressman SB,Breakefield XO, Ozelius LJ, Pramstaller PP, Klein C. Mutations in DYT1: extensionof the phenotypic and mutational spectrum. Neurology. 2004 Feb 10;62(3):395-400.
Ozelius LJ, Hewett JW, Page CE, Bressman SB, Kramer PL, Shalish C, de Leon D, Brin MF, Raymond D, Corey DP, Fahn S, Risch NJ, Buckler AJ, Gusella JF,Breakefield XO. The early-onset torsion dystonia gene (DYT1) encodes anATP-binding protein. Nat Genet. 1997 Sep;17(1):40-8.
Rostasy K, Augood SJ, Hewett JW, Leung JC, Sasaki H, Ozelius LJ, Ramesh V,Standaert DG, Breakefield XO, Hedreen JC. TorsinA protein and neuropathology inearly onset generalized dystonia with GAG deletion. Neurobiol Dis. 2003Feb;12(1):11-24.
Sibbing D, Asmus F, König IR, Tezenas du Montcel S, Vidailhet M, Sangla S,Oertel WH, Brice A, Ziegler A, Gasser T, Bandmann O. Candidate gene studies infocal dystonia. Neurology. 2003 Oct 28;61(8):1097-101.
Walker RH, Shashidharan P. Developments in the molecular biology of DYT1dystonia. Mov Disord. 2003 Oct;18(10):1102-7. Review.

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Subjects: Genetics & Heredity

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Rui Liu

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Update Date: 25 Dec 2020

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