A Common Polymorphism of the SRD5A2 Gene is Not Associated With Male-to-Female and Female-to-Male Transsexualism

Transsexualism Clinical Trial

Official title: Association Study of a SRD5A2 SNP and Transsexualism.

Status Completed

Clinical Trial Summary

Genetic variations, i.e. polymorphisms, may be associated with gender dysphoria, e.g. transsexualism. This study aims to identify such variations.

Clinical Trial Description

Context: Early developmental exposure of the brain to sex steroids may play a role in the etiology of transsexualism.

Objective: To assess the association between transsexualism and allele and genotype frequencies of the steroid 5-alpha reductase (SRD5A2) Val89Leu polymorphism.

Design and Patients: We performed a case-control study of 100 male-to-female (MtF) transsexuals, 47 female-to-male (FtM) transsexuals, 755 male controls, and 915 female controls. DNA was extracted from buccal swabs and genotypes were determined by polymerase chain reaction.

Results: SRD5A2 Val89Leu allele frequencies (SRD5A2 V: 137/200 [69%] and SRD5A2 L: 63/200 [31%] vs. SRD5A2 V: 1065/1510 [71%] and SRD5A2 L: 445/1510 [29%], respectively; p=0.6; Odds Ratio [OR] 1.10; 95% Confidence Interval [CI] 0.76-1.58) and genotype distributions (SRD5A2 V/V+V/L: 92/100 [92%] and L/L 8/100 [8%] vs. SRD5A2 V/V+V/L: 683/755 [91%] and L/L 72/755 [9%], respectively, p=0.7; OR 0.82; 95% CI 0.24-2.84) were not significantly different between MtF transsexuals and male controls. SRD5A2 Val89Leu allele frequencies (SRD5A2 V: 70/94 [74%] and SRD5A2 L: 24/94 [26%] vs. SRD5A2 V: 1253/1830 [69%] and SRD5A2 L: 573/1830 [31%], respectively; p=0.3; OR 0.75; 95% CI 0.45-1.26) and genotype distributions (SRD5A2 V/V+V/L: 44/47 [93%] and L/L 3/47 [7%] vs. SRD5A2 V/V+V/L: 823/915 [90%] and L/L 92/915 [10%], respectively, p=0.6; OR 0.61; 95% CI 0.11-3.32) were also not significantly different between FtM transsexuals and female controls. Of note, there was no gender-specific genotype distribution among controls.

Conclusions: The SRD5A2 Val89Leu polymorphism is not associated with transsexualism and is no candidate gene of this condition. ;

Study Design

Observational Model: Case Control, Time Perspective: Retrospective

Related Conditions & MeSH terms

• Transsexualism

• NCT number: NCT00435513
• Study type: Observational
• Source: Medical University of Vienna
• Status: Completed
• Phase: Phase 0
• Start date: March 2007
• Completion date: July 2008