No association between TPH2 gene polymorphisms and ADHD in a UK sample

Karen Sheehan, Ziarih Hawi, Michael Gill, Lindsey Kent

Research output: Contribution to journalArticleResearchpeer-review

21 Citations (Scopus)


Tryptophan Hydroxylase 2 (TPH2) is the rate-limiting enzyme in the biosynthesis of serotonin which is exclusively expressed in the brain. Recent molecular studies reported significant association between markers mapped to TPH2 and psychiatric conditions including ADHD. We have examined four single nucleotide polymorphisms (SNPs) two of which (rs1843809, rs1386493) were reported to associate with ADHD in an Irish ADHD sample. Transmission disequilibrium analysis revealed no significant association between any of these markers and ADHD. Dividing by the sex of the transmitting parent has also failed to replicate the previously reported paternal over-transmission of the associated alleles to ADHD probands. A larger sample size will be required to clarify if TPH2 alleles are or are not associated with ADHD.

Original languageEnglish
Pages (from-to)105-107
Number of pages3
JournalNeuroscience Letters
Issue number2
Publication statusPublished - 29 Jan 2007
Externally publishedYes


  • Attention Deficit Hyperactivity Disorder (ADHD)
  • Genetic association
  • Serotonergic system
  • Transmission disequilibrium test (TDT)
  • Tryptophan Hydroxylase 2 (TPH2)

Cite this