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Tryptophan hydroxylase 2 (TPH2) is an isozyme of tryptophan hydroxylase found in vertebrates. In humans, TPH2 is primarily expressed in the serotonergic neurons of the brain, with the highest expression in the raphe nucleus of the midbrain. Until the discovery of TPH2 in 2003,[5] serotonin levels in the central nervous system were believed to be regulated by serotonin synthesis in peripheral tissues, in which tryptophan hydroxylase is the dominant form.[6]

Available structures
PDBOrtholog search: PDBe RCSB
AliasesTPH2, ADHD7, NTPH, tryptophan hydroxylase 2
External IDsOMIM: 607478 MGI: 2651811 HomoloGene: 27831 GeneCards: TPH2
Gene location (Human)
Chromosome 12 (human)
Chr.Chromosome 12 (human)[1]
Chromosome 12 (human)
Genomic location for TPH2
Genomic location for TPH2
Band12q21.1Start71,938,845 bp[1]
End72,186,618 bp[1]
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC)Chr 12: 71.94 – 72.19 MbChr 10: 115.08 – 115.19 Mb
PubMed search[3][4]
View/Edit HumanView/Edit Mouse



Tryptophan hydroxylase (TPH; EC is the rate-limiting enzyme in the synthesis of serotonin (5-hydroxytryptamine, or 5HT). 5HT is causally involved in numerous central nervous activities, and it has several functions in peripheral tissues, including the maintenance of vascular tone and gut motility.[supplied by OMIM][7]

See alsoEdit


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000139287 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000006764 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:".
  4. ^ "Mouse PubMed Reference:".
  5. ^ Walther DJ, Peter JU, Bashammakh S, Hörtnagl H, Voits M, Fink H, Bader M (Jan 2003). "Synthesis of serotonin by a second tryptophan hydroxylase isoform". Science. 299 (5603): 76. doi:10.1126/science.1078197. PMID 12511643.
  6. ^ Zill P, Büttner A, Eisenmenger W, Möller HJ, Ackenheil M, Bondy B (2005). "Analysis of tryptophan hydroxylase I and II mRNA expression in the human brain: a post-mortem study". Journal of Psychiatric Research. 41 (1–2): 168–73. doi:10.1016/j.jpsychires.2005.05.004. PMID 16023677.
  7. ^ "Entrez Gene: TPH2 tryptophan hydroxylase 2".

Further readingEdit

  • Walther DJ, Peter JU, Bashammakh S, Hörtnagl H, Voits M, Fink H, Bader M (Jan 2003). "Synthesis of serotonin by a second tryptophan hydroxylase isoform". Science. 299 (5603): 76. doi:10.1126/science.1078197. PMID 12511643.
  • Walther DJ, Bader M (Nov 2003). "A unique central tryptophan hydroxylase isoform". Biochemical Pharmacology. 66 (9): 1673–80. doi:10.1016/S0006-2952(03)00556-2. PMID 14563478.
  • Zill P, Baghai TC, Zwanzger P, Schüle C, Eser D, Rupprecht R, Möller HJ, Bondy B, Ackenheil M (Nov 2004). "SNP and haplotype analysis of a novel tryptophan hydroxylase isoform (TPH2) gene provide evidence for association with major depression". Molecular Psychiatry. 9 (11): 1030–6. doi:10.1038/ PMID 15124006.
  • Breidenthal SE, White DJ, Glatt CE (Jun 2004). "Identification of genetic variants in the neuronal form of tryptophan hydroxylase (TPH2)". Psychiatric Genetics. 14 (2): 69–72. doi:10.1097/01.ypg.0000107929.32051.58. PMID 15167691.
  • De Luca V, Mueller DJ, Tharmalingam S, King N, Kennedy JL (Oct 2004). "Analysis of the novel TPH2 gene in bipolar disorder and suicidality". Molecular Psychiatry. 9 (10): 896–7. doi:10.1038/ PMID 15197398.
  • Harvey M, Shink E, Tremblay M, Gagné B, Raymond C, Labbé M, Walther DJ, Bader M, Barden N (Nov 2004). "Support for the involvement of TPH2 gene in affective disorders". Molecular Psychiatry. 9 (11): 980–1. doi:10.1038/ PMID 15263906.
  • Zill P, Büttner A, Eisenmenger W, Möller HJ, Bondy B, Ackenheil M (Oct 2004). "Single nucleotide polymorphism and haplotype analysis of a novel tryptophan hydroxylase isoform (TPH2) gene in suicide victims". Biological Psychiatry. 56 (8): 581–6. doi:10.1016/j.biopsych.2004.07.015. PMID 15476687.
  • Zhang X, Gainetdinov RR, Beaulieu JM, Sotnikova TD, Burch LH, Williams RB, Schwartz DA, Krishnan KR, Caron MG (Jan 2005). "Loss-of-function mutation in tryptophan hydroxylase-2 identified in unipolar major depression". Neuron. 45 (1): 11–6. doi:10.1016/j.neuron.2004.12.014. PMID 15629698.
  • Coon H, Dunn D, Lainhart J, Miller J, Hamil C, Battaglia A, Tancredi R, Leppert MF, Weiss R, McMahon W (May 2005). "Possible association between autism and variants in the brain-expressed tryptophan hydroxylase gene (TPH2)". American Journal of Medical Genetics Part B. 135B (1): 42–6. doi:10.1002/ajmg.b.30168. PMID 15768392.
  • Sheehan K, Lowe N, Kirley A, Mullins C, Fitzgerald M, Gill M, Hawi Z (Oct 2005). "Tryptophan hydroxylase 2 (TPH2) gene variants associated with ADHD". Molecular Psychiatry. 10 (10): 944–9. doi:10.1038/ PMID 15940290.
  • Shamir A, Shaltiel G, Levi I, Belmaker RH, Agam G (2005). "Postmortem parietal cortex TPH2 expression is not altered in schizophrenic, unipolar-depressed, and bipolar patients vs control subjects". Journal of Molecular Neuroscience. 26 (1): 33–7. doi:10.1385/JMN:26:1:033. PMID 15968084.
  • Brown SM, Peet E, Manuck SB, Williamson DE, Dahl RE, Ferrell RE, Hariri AR (Sep 2005). "A regulatory variant of the human tryptophan hydroxylase-2 gene biases amygdala reactivity". Molecular Psychiatry. 10 (9): 884–8, 805. doi:10.1038/ PMID 16044172.
  • Walitza S, Renner TJ, Dempfle A, Konrad K, Wewetzer CH, Halbach A, Herpertz-Dahlmann B, Remschmidt H, Smidt J, Linder M, Flierl L, Knölker U, Friedel S, Schäfer H, Gross C, Hebebrand J, Warnke A, Lesch KP (Dec 2005). "Transmission disequilibrium of polymorphic variants in the tryptophan hydroxylase-2 gene in attention-deficit/hyperactivity disorder". Molecular Psychiatry. 10 (12): 1126–32. doi:10.1038/ PMID 16116490.
  • Canli T, Congdon E, Gutknecht L, Constable RT, Lesch KP (Nov 2005). "Amygdala responsiveness is modulated by tryptophan hydroxylase-2 gene variation". Journal of Neural Transmission. 112 (11): 1479–85. doi:10.1007/s00702-005-0391-4. PMID 16245070.
  • Mössner R, Freitag CM, Gutknecht L, Reif A, Tauber R, Franke P, Fritze J, Wagner G, Peikert G, Wenda B, Sand P, Rietschel M, Garritsen H, Jacob C, Lesch KP, Deckert J (Jul 2006). "The novel brain-specific tryptophan hydroxylase-2 gene in panic disorder". Journal of Psychopharmacology. 20 (4): 547–52. doi:10.1177/0269881106059704. PMID 16401665.
  • De Luca V, Hlousek D, Likhodi O, Van Tol HH, Kennedy JL, Wong AH (Feb 2006). "The interaction between TPH2 promoter haplotypes and clinical-demographic risk factors in suicide victims with major psychoses". Genes, Brain, and Behavior. 5 (1): 107–10. doi:10.1111/j.1601-183X.2005.00182.x. PMID 16436194.
  • Delorme R, Durand CM, Betancur C, Wagner M, Ruhrmann S, Grabe HJ, Nygren G, Gillberg C, Leboyer M, Bourgeron T, Courtet P, Jollant F, Buresi C, Aubry JM, Baud P, Bondolfi G, Bertschy G, Perroud N, Malafosse A (Jul 2006). "No human tryptophan hydroxylase-2 gene R441H mutation in a large cohort of psychiatric patients and control subjects". Biological Psychiatry. 60 (2): 202–3. doi:10.1016/j.biopsych.2005.12.014. PMID 16581035.
  • Carkaci-Salli N, Flanagan JM, Martz MK, Salli U, Walther DJ, Bader M, Vrana KE (Sep 2006). "Functional domains of human tryptophan hydroxylase 2 (hTPH2)". The Journal of Biological Chemistry. 281 (38): 28105–12. doi:10.1074/jbc.M602817200. PMID 16864580.