Brain development, brain functioning, growth and metabolic aspects in the clinical management of transsexual adolescents.

The clinical management of transsexual adolescents of the VUmc consists of
suppression of puberty with GnRH analogues from the moment the juvenile
transsexuals reach pubertal stage 2 according to Tanner. From the age of 16
they receive cross-sex hormones in addition to the puberty delaying medication.
Treatment at this age and the use of GnRH agonists as a diagnostic aid is still
controversial. Knowing more about the effect of hormone treatment is not only
of theoretical interest but also of very great clinical relevance. The
hypothesis of this study is that brain functioning and brain structure of
transsexual teenagers treated with GnRH agonists is according healthy
individuals without transsexuality.
Little is known about etiological aspects of transsexuality. Transsexuality is
associated with atypical sex hormone levels during pregnancy. The hypothesis is
that in transsexualism the development of brain structures and brain
functioning is in the direction of the desired sex instead of the biological
sex.
The VUmc gender team for children and adolescents assesses early-onset
transsexuals on a regular basis. This group is unique since, according to their
parents, these transsexual children and adolescents did never show gender
related behaviour corresponding with their biological sex, neither did they use
cross-sex hormones, which might be influential on their brain development. We
therefore believe that the best chances to find biological differences in brain
development and function between transsexuals and non-transsexual are in this
group. As the VUmc assesses by far the largest number of transsexual
adolescents in the world, we are in a unique position to generate findings that
may give us insight in the aetiology of the phenomenon and the effects of these
pituary agonists on brain development

The present study will focus on the consequences of long-term delay of puberty
induced by treatment with Decapeptyl-CR. We will investigate the effects of
this treatment in regard to brain functioning, brain development, various
endocrine, metabolic and anthropometric aspects before, during and after
treatment with Decapeptyl-CR alone and in combination with cross-sex hormones
in juvenile transsexuals. Hereby we will focus on sex differences between
transsexual adolescents and similar aged individuals of both sexes by
investigating brain development and brain functioning, as well as on possible
determinants of the aetiology of transsexuality by means of structural and
functional MRI and family pedigree research.

This study is an observational, non invasive cross-sectional (with longitudinal
continuation) prospective follow-up study.

There are no risks.
We use MR imaging, which is a non-invasive technique, there is no potential
harm from radiation. We measure salivary testosterone instead of blood samples
which is less invasive. All investigations will take place on the same day to
minimize the effort for the subjects. We practise the cognition tasks in
advance to reduce the stress of the subjects during scanning. We provide video,
audio and photo material and s dummy scanner will be available to prepare the
subjects for the MRI-scanner. If the extend of the burden is too much, the
scanning will not be continued.