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Normal Function
The DOK7 gene provides instructions for making a protein that is necessary for the formation of connections between nerve cells and muscle cells, which occur in the neuromuscular junction. The neuromuscular junction is the area between the ends of nerve cells and muscle cells where signals are relayed to trigger muscle movement. The Dok-7 protein participates in turning on (activating) a protein called MuSK that plays a key role in organizing the various proteins important for the development and maintenance of the neuromuscular junction. In particular, the MuSK protein is involved in concentrating a protein called the acetylcholine receptor (AChR) in the muscle membrane at the neuromuscular junction." The AChR protein is critical for signaling between nerve and muscle cells, which is necessary for movement.
Health Conditions Related to Genetic Changes
Congenital myasthenic syndrome
At least 45 mutations in the DOK7 gene have been found to cause congenital myasthenic syndrome. A mutation that frequently occurs is the addition of four DNA building blocks (nucleotides) in the DOK7 gene (written as 1124_1127dupTGCC). Mutations in this gene lead to the production of a defective Dok-7 protein that cannot activate the MuSK protein. As a result, less AChR is present in the neuromuscular junction, which reduces signaling between nerve and muscle cells. These signaling abnormalities lead to decreased muscle movement and the muscle weakness characteristic of congenital myasthenic syndrome. For reasons that are unclear, people with mutations in the DOK7 gene tend to have muscle weakness in the shoulders, hips, and limbs, known as limb-girdle muscle weakness.
More About This Health ConditionOther Names for This Gene
- C4orf25
- CMS1B
- Dok-7
- DOK7_HUMAN
- downstream of tyrosine kinase 7
Additional Information & Resources
Tests Listed in the Genetic Testing Registry
Scientific Articles on PubMed
Catalog of Genes and Diseases from OMIM
References
- Beeson D, Webster R, Cossins J, Lashley D, Spearman H, Maxwell S, Slater CR, Newsom-Davis J, Palace J, Vincent A. Congenital myasthenic syndromes and the formation of the neuromuscular junction. Ann N Y Acad Sci. 2008;1132:99-103. doi: 10.1196/annals.1405.049. Citation on PubMed
- Engel AG, Shen XM, Selcen D, Sine SM. What have we learned from the congenital myasthenic syndromes. J Mol Neurosci. 2010 Jan;40(1-2):143-53. doi: 10.1007/s12031-009-9229-0. Epub 2009 Aug 18. Citation on PubMed or Free article on PubMed Central
- Engel AG. Current status of the congenital myasthenic syndromes. Neuromuscul Disord. 2012 Feb;22(2):99-111. doi: 10.1016/j.nmd.2011.10.009. Epub 2011 Nov 21. Citation on PubMed or Free article on PubMed Central
- Kinali M, Beeson D, Pitt MC, Jungbluth H, Simonds AK, Aloysius A, Cockerill H, Davis T, Palace J, Manzur AY, Jimenez-Mallebrera C, Sewry C, Muntoni F, Robb SA. Congenital myasthenic syndromes in childhood: diagnostic and management challenges. J Neuroimmunol. 2008 Sep 15;201-202:6-12. doi: 10.1016/j.jneuroim.2008.06.026. Epub 2008 Aug 15. Citation on PubMed
- Muller JS, Herczegfalvi A, Vilchez JJ, Colomer J, Bachinski LL, Mihaylova V, Santos M, Schara U, Deschauer M, Shevell M, Poulin C, Dias A, Soudo A, Hietala M, Aarimaa T, Krahe R, Karcagi V, Huebner A, Beeson D, Abicht A, Lochmuller H. Phenotypical spectrum of DOK7 mutations in congenital myasthenic syndromes. Brain. 2007 Jun;130(Pt 6):1497-506. doi: 10.1093/brain/awm068. Epub 2007 Apr 17. Citation on PubMed
- Selcen D, Milone M, Shen XM, Harper CM, Stans AA, Wieben ED, Engel AG. Dok-7 myasthenia: phenotypic and molecular genetic studies in 16 patients. Ann Neurol. 2008 Jul;64(1):71-87. doi: 10.1002/ana.21408. Citation on PubMed or Free article on PubMed Central
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