Related Experiment Videos
TPH2 polymorphisms may modify clinical picture in treatment-resistant depression
Sami Anttila1, Merja Viikki, Kaija Huuhka
1University of Tampere, Medical School, 33014 University of Tampere, Finland.
Neuroscience Letters
|August 15, 2009
Summary
Investigating tryptophan hydroxylase 2 (TPH2) gene variants in electroconvulsive therapy (ECT) for major depression revealed no direct link to treatment response. However, one TPH2 polymorphism (rs1386494) correlated with depression severity.
Area of Science:
- Neuroscience
- Genetics
- Psychiatry
Background:
- Major depressive disorder (MDD) is a debilitating condition with variable treatment responses.
- Electroconvulsive therapy (ECT) is an effective treatment for severe, treatment-resistant depression.
- Genetic factors, including tryptophan hydroxylase 2 (TPH2) polymorphisms, are explored for their role in depression and treatment outcomes.
Purpose of the Study:
- To investigate the association between TPH2 gene polymorphisms (rs1386494 and rs1843809) and treatment response to ECT in patients with treatment-resistant MDD.
- To explore the relationship between these TPH2 polymorphisms and the severity of depression.
Main Methods:
- A cohort of 119 patients with treatment-resistant MDD undergoing ECT was studied.
- Genotyping was performed for TPH2 polymorphisms rs1386494 and rs1843809.
- Treatment response was assessed using the Montgomery and Asberg Depression Rating Scale (MADRS) scores, with remission defined as post-treatment MADRS <8 and non-response as >15.
Main Results:
- Neither rs1386494 nor rs1843809 showed a significant association with treatment response to ECT.
- Patients with the TPH2 rs1386494 A/A genotype exhibited significantly higher pre-ECT MADRS scores compared to A/G+G/G carriers (p<0.001).
- A/A genotype carriers demonstrated a greater reduction in MADRS scores during ECT treatment (p=0.03), suggesting a potential influence on depression severity.
Conclusions:
- The TPH2 rs1386494 polymorphism may be linked to the severity of treatment-resistant depression.
- ECT appears capable of mitigating a potentially genetically influenced, more severe depressive phenotype associated with the TPH2 rs1386494 A/A genotype.
Related Concept Videos
01:29Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
Genetic variations significantly influence drug response through pharmacokinetics, receptor interactions, and biologic milieu modifications. Pharmacokinetic alterations impact drug metabolism and clearance, affecting efficacy and toxicity. Variants in drug-metabolizing enzymes, such as CYP2C9 and CYP2C19, alter drug activation and elimination. For example, CYP2C9 loss-of-function variants require lower warfarin doses to prevent excessive bleeding, while CYP2C19 variants reduce clopidogrel...
01:11Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Genetic polymorphisms in drug targets have emerged as critical determinants of interindividual variability in drug response and toxicity. Pharmacogenomic investigations increasingly focus on identifying these variations to personalize and optimize therapeutic interventions. A drug target may be a receptor, enzyme, or signaling protein involved in pharmacologic responses or disease-related pathways. While early pharmacogenetic studies focused primarily on drug metabolism, current research...
01:27Pharmacogenetics of Phase II Enzymes: N-acetyltransferase, Thiopurine S-methyltransferase, UDP-glucuronosyltransferase
Phase II biotransformation reactions are essential for detoxifying and eliminating xenobiotics, including many pharmaceutical compounds. These reactions typically involve conjugation, the covalent attachment of polar endogenous groups such as glucuronic acid, sulfate, methyl, or acetyl moieties to functional groups introduced during Phase I metabolism. The resulting conjugates are more water-soluble, enabling efficient renal or biliary excretion.The major classes of Phase II enzymes include...
01:27Pharmacogenetics of Drug Metabolism: Overview
Genetic polymorphism in drug metabolism is crucial to the inter-individual variability observed in drug responses. Drug metabolism primarily involves the chemical modification of drugs and other xenobiotics to enhance their elimination by increasing their polarity. Two main classes of enzymes mediate this biotransformation process: Phase I enzymes, primarily cytochrome P450s, catalyze oxidation and reduction reactions, while other enzymes, such as esterases, mediate hydrolysis, and Phase II...
01:28Pharmacogenetics of Phase I Enzymes: Cytochrome P450 Isozymes
Cytochrome P450 (CYP450) enzymes are a superfamily of heme-containing monooxygenases that play a pivotal role in Phase I drug metabolism by catalyzing oxidation and reduction reactions.These enzymes transform lipophilic xenobiotics into more hydrophilic metabolites, facilitating subsequent Phase II conjugation and eventual excretion. The CYP450 family is classified into families (e.g., CYP1–CYP3) and subfamilies (e.g., CYP2A, CYP2C), based on amino acid sequence homology.CYP450 isoenzymes,...
01:27Principles of Pharmacogenetics: Types of Genetic Variants
The human genome is over 99.9% identical between individuals, yet genetic differences exist at millions of bases. The human genome contains approximately 3 million variant positions per individual, many of which are heterozygous, contributing to genetic diversity and individual traits. Genetic variations include single-nucleotide polymorphisms (SNPs), insertions, deletions, and copy number variations (CNVs).SNPs, the most common variation, involve single-base changes in DNA. These can be...