Intrinsic cerebral connectivity analysis in an untreated Female to Male Transsexual subject.

Transsexualism is a gender identity disorder (GID) whose symptomatology could involve cognitive, neurobiological and psychological variance from biological sex standard. Several evidences support the hypothesis of a structural and functional brain reorganization in transgender subjects, with a different impact for Male-to-Female and Female-to-Male subjects. Here we used resting-state fMRI (rs-fMRI) to understand the similarities between the spontaneous brain connectivity of an untreated Female-to-Male (FtM) and two male and female control groups. Both seed-voxel and atlas based region-of-interest (ROI) approach were used. Brain areas sensitive to gender dimorphism like left lingual gyrus and precuneus showed strong similarities between FtM subject and female control group respect to control males, with comparable extension and location of functional connectivity maps. No difference between seed-voxel results in FtM subject and females were found. ROI analysis confirmed these evidences highlighting a pattern of bilateral differences between FtM subject and male. These data support the idea that untreated Female-to-Male transgender shows a functional connectivity profile comparable to female control subjects.