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Lauren Hare, Pascal
Bernard, Francisco J. Sánchez, Paul N. Baird,
Eric Vilain, Trudy Kennedy,
and Vincent R. Harley Accepted: Aug 25,
2008 Abstract 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 beta (ER?), and aromatase (CYP19)
genes. Methods:
Subject-control analysis included 112
male-to-female
transsexuals and 258
non-transsexual male controls. Associations and
interactions were
investigated between CAG repeat length in the AR
gene, CA repeat length in
the ER? 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 controls (p=0.04). No
associations for
transsexualism were evident in repeat lengths for
CYP19 or ER? ?genes.
Individuals were then classified as short or long
for each gene
polymorphism based on 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 may be
partly mediated through the androgen receptor. © 2008 Society of
Biological
Psychiatry
Androgen
Receptor (AR) Repeat Length Polymorphism Associated
with
Male-to-Female
Transsexualism
