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Pathway Description
Segawa Syndrome
Homo sapiens
Disease Pathway
Segawa syndrome is a condition in which the affected individual has a clumsy or unusual gait, and experiences involuntary muscle contractions and uncontrolled movements (dystonia). Some cases are mild, while others can be severe. The beginning signs of this condition are dystonia in the legs, and clubfeet. The cause of this condition is a mutation in the GCH1 gene. Tetrahydrobiopterin is an important compound in the production of neurotransmitters, specifically dopamine and serotonin, and the processing of quite a few amino acids, The mutation on GCH1 causes GTP cyclohydrase 1 production to be reduced or absent which causes the first three steps of tetrahydrobiopterin biosynthesis to be compromised. Dopamine is imperative in maintaining smooth muscle movements, which is why patients with Segawa syndrome experience movement problems and an unusual gait.
References
Segawa Syndrome References
[Metagen: SEGAWA SYNDROME](http://metagene.de/program/d.prg?id_d=391)
[OMIM: 128230](http://omim.org/entry/128230})
Segawa M, Hosaka A, Miyagawa F, Nomura Y, Imai H: Hereditary progressive dystonia with marked diurnal fluctuation. Adv Neurol. 1976;14:215-33.
Pubmed: 945938
Harwood G, Hierons R, Fletcher NA, Marsden CD: Lessons from a remarkable family with dopa-responsive dystonia. J Neurol Neurosurg Psychiatry. 1994 Apr;57(4):460-3.
Pubmed: 8163996
Brautigam C, Steenbergen-Spanjers GC, Hoffmann GF, Dionisi-Vici C, van den Heuvel LP, Smeitink JA, Wevers RA: Biochemical and molecular genetic characteristics of the severe form of tyrosine hydroxylase deficiency. Clin Chem. 1999 Dec;45(12):2073-8.
Pubmed: 10585338
Pterine Biosynthesis References
Lehninger, A.L. Lehninger principles of biochemistry (4th ed.) (2005). New York: W.H Freeman.
Salway, J.G. Metabolism at a glance (3rd ed.) (2004). Alden, Mass.: Blackwell Pub.
Thony B, Auerbach G, Blau N: Tetrahydrobiopterin biosynthesis, regeneration and functions. Biochem J. 2000 Apr 1;347 Pt 1:1-16.
Pubmed: 10727395
Longo N: Disorders of biopterin metabolism. J Inherit Metab Dis. 2009 Jun;32(3):333-42. doi: 10.1007/s10545-009-1067-2. Epub 2009 Feb 9.
Pubmed: 19234759
Crabtree MJ, Channon KM: Synthesis and recycling of tetrahydrobiopterin in endothelial function and vascular disease. Nitric Oxide. 2011 Aug 1;25(2):81-8. doi: 10.1016/j.niox.2011.04.004. Epub 2011 Apr 22.
Pubmed: 21550412
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