Korean J Psychopharmacol.  2005 Sep;16(5):406-415.

The Tryptophan Hydroxylase A218C Polymorphism in Patients with Bipolar Disorder

• Kim WT
• Kim SK

Abstract

OBJECTIVE
This study has been carried out to explore the genetic causes of bipolar disorder by comparing the frequency of Tryptophan Hydroxylase (TPH) A218C polymorphism between bipolar disorder patients and normal controls, and to explore the relation between clinical characteristics of bipolar disorder patients and TPH polymorphism. METHODS: The genotype and allele frequencies of TPH in the genome of 113 hospitalized patients with bipolar disorder was compared with those of 124 normal control subjects using polymerase chain reaction and restriction fragment length polymorphism. The association between TPH A218C polymorphism and clinical characteristics in bipolar disorder patients were explored. RESULTS: The distributions of TPH A218C polymorphism between the patients with bipolar disorder and normal control subjects show no difference statistically. There was a significant difference in the distribution of TPH genotype by clinical characteristics. The frequency of C allele is significantly higher in patients with a history of suicidal attempts. The frequency of A allele is significantly higher in patients with family history of bipolar disorder. CONCLUSION: This study suggests that suicidal attempts and family history in the patients with bipolar disorder are clearly associated with TPH A218C polymorphism and may explain, in part, the biological basis for these typologies.

Keyword

Bipolar disorder; TPH gene; Suicide; Family history

MeSH Terms

Alleles
Bipolar Disorder*
Gene Frequency
Genome
Genotype
Humans
Polymerase Chain Reaction
Polymorphism, Restriction Fragment Length
Suicide
Tryptophan Hydroxylase*
Tryptophan*
Tryptophan
Tryptophan Hydroxylase