Intrinsic cerebral connectivity analysis in an untreated female-to-male transsexual subject: a first attempt using resting-state fMRI.

BACKGROUND/AIMS: Transsexualism is a gender identity disorder 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 (FtM) subjects. Here we used resting-state fMRI to understand the similarities between the spontaneous brain connectivity of an untreated FtM subject and two male and female control groups. METHODS: Both seed-voxel and atlas-based region-of-interest (ROI) approaches were used. RESULTS: Brain areas sensitive to gender dimorphism like left lingual gyrus and precuneus showed strong similarities between the FtM subject and female control group with respect to control males, with comparable extension and location of functional connectivity maps. ROI analysis confirmed this evidence, highlighting a greater pattern of differences between the FtM subject and males and the FtM subject and females. No difference between seed-voxel results in the FtM subject and females was found. CONCLUSION: These data partially support the idea that untreated FtM transgender shows a functional connectivity profile comparable to female control subjects.