Disorder-specific genetic factors in obsessive-compulsive disorder: A comprehensive meta-analysis

Area of Science:

• Neurogenetics
• Psychiatric Genetics

Background:

• Understanding the genetic underpinnings of obsessive-compulsive disorder (OCD) is crucial for identifying disorder-specific factors.
• Previous research indicates associations between OCD and specific genetic polymorphisms, including serotonin transporter gene (5-HTTLPR), HTR2A, and catechol-O-methyltransferase (COMT) in males.

Purpose of the Study:

• To conduct the first comprehensive meta-analysis to determine the specificity of 5-HTTLPR, HTR2A, and COMT polymorphisms to OCD.
• To investigate whether these polymorphisms are associated with other psychiatric disorders.

Main Methods:

• A systematic meta-analysis of genetic association studies for OCD and other psychiatric disorders was performed.
• Included studies were published in any language or country, encompassing case-control and family-based designs.
• Data from 290 studies (47,358 cases, 68,942 controls, 2,443 trios) were analyzed, focusing on disorders with at least five datasets.

Main Results:

• The meta-analysis confirmed significant associations between OCD and polymorphisms in 5-HTTLPR, HTR2A, and COMT (in males).
• These polymorphisms showed minimal to no association with other major psychiatric conditions, including mood disorders, bipolar disorder, panic disorder, schizophrenia, and alcohol dependence.
• Obsessive-compulsive disorder exhibited a significantly stronger association with specific alleles of these polymorphisms compared to most other disorders studied.

Conclusions:

• The investigated polymorphisms (5-HTTLPR, HTR2A, and COMT in males) appear to be relatively specific to obsessive-compulsive disorder.
• These findings contribute to understanding the distinct genetic etiology of OCD.
• Results were consistent across different ancestral groups, study designs, and diagnostic systems.