Background
There is a likely genetic component to transsexualism, and genes involved in sex steroidogenesis
are good candidates. We explored the specific hypothesis that male-to-female transsexualism
is associated with gene variants responsible for undermasculinization and/or feminization.
Specifically, we assessed the role of disease-associated repeat length polymorphisms
in the androgen receptor (AR), estrogen receptor β (ERβ), and aromatase (CYP19) genes.
Methods
Subject-control analysis included 112 male-to-female transsexuals and 258 non-transsexual
males. Associations and interactions were investigated between CAG repeat length in
the AR gene, CA repeat length in the ERβ gene, and TTTA repeat length in the CYP19 gene and male-to-female transsexualism.
Results
A significant association was identified between transsexualism and the AR allele, with transsexuals having longer AR repeat lengths than non-transsexual male control subjects (p = .04). No associations for transsexualism were evident in repeat lengths for CYP19 or ERβ genes. Individuals were then classified as short or long for each gene polymorphism
on the basis of control median polymorphism lengths in order to further elucidate
possible combined effects. No interaction associations between the three genes and
transsexualism were identified.
Conclusions
This study provides evidence that male gender identity might be partly mediated through
the androgen receptor.
Key Words
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Article Info
Publication History
Published online: October 30, 2008
Accepted:
August 25,
2008
Received in revised form:
August 13,
2008
Received:
April 15,
2008
Identification
Copyright
© 2009 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.
