Tryptophan Hydroxylase 1 (TPH1)

TPH1 encodes a member of the aromatic amino acid hydroxylase family. The encoded protein catalyzes the first and rate limiting step in the biosynthesis of serotonin, an important hormone and neurotransmitter. Mutations in this gene have been associated with an elevated risk for a variety of diseases and disorders, including schizophrenia, somatic anxiety, anger-related traits, bipolar disorder, suicidal behavior, addictions, and others.

Tryptophan hydroxylase is important for the brain. However, Tph1 is not detected in the brain. Nevertheless the effect of variations in the TPH1 gene on brain-related variables, such as personality traits and neuropsychiatric disorders, has been studied. One human mutant of TPH1, A218C found in intron 7, is highly associated with schizophrenia.