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

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00435513
Recruitment Status : Completed
First Posted : February 15, 2007
Last Update Posted : May 5, 2015
Information provided by (Responsible Party):
Clemens Tempfer, Medical University of Vienna

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

Condition or disease

Detailed 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.

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Study Type : Observational
Actual Enrollment : 1770 participants
Observational Model: Case-Control
Time Perspective: Retrospective
Official Title: Association Study of a SRD5A2 SNP and Transsexualism.
Study Start Date : March 2007
Actual Primary Completion Date : May 2008
Actual Study Completion Date : July 2008

Transsexual group
Female-to-male and male-to-female transsexuals
Healthy blood donors

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 80 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Probability Sample
Study Population
Female-to-male transsexuals and male-to-female transsexuals

Inclusion Criteria:

  • transsexual individuals as defined by DSM IV criteria

Exclusion Criteria:

  • unwillingness to participate

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00435513

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University of Vienna, Vienna, Austria
Vienna, Austria, 1090
Sponsors and Collaborators
Medical University of Vienna
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Principal Investigator: Clemens B Tempfer, MD Univ. of Vienna
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Responsible Party: Clemens Tempfer, Prof. Clemens Tempfer, MD, Medical University of Vienna Identifier: NCT00435513    
Other Study ID Numbers: 000001
First Posted: February 15, 2007    Key Record Dates
Last Update Posted: May 5, 2015
Last Verified: May 2015