Evidence for gender-specific endophenotypes in high-functioning autism spectrum disorder during empathy.

Despite remarkable behavioral gender differences in patients with autism spectrum disorder (ASD), and growing evidence for a diminished male : female ratio for the putative "male disorder" ASD, aspects of gender are not addressed accordingly in ASD research. Our study aims at filling this gap by exploring empathy abilities in a group of 28 patients with high-functioning ASD and 28 gender-, age- and education-matched non-autistic subjects, for the first time by means of functional neuroimaging (fMRI). In an event-related fMRI paradigm, emotional ("E") and neutral ("N") video clips presented actors telling self-related short stories. After each clip, participants were asked to indicate their own emotion and its intensity as well as the emotion and intensity perceived for the actor. Behaviorally, we found significantly less empathic responses in the overall ASD group compared with non-autistic subjects, and inadequate emotion recognition for the neutral clips in the female ASD group compared with healthy women. Neurally, increased activation of the bilateral medial frontal gyrus was found in male patients compared with female patients, a pattern which was not present in the non-autistic group. Additionally, autistic women exhibited decreased activation of midbrain and limbic regions compared with non-autistic women, whereas there was no significant difference within the male group. While we did not find a fundamental empathic deficit in autistic patients, our data propose different ways of processing empathy in autistic men and women, suggesting stronger impairments in cognitive aspects of empathy/theory of mind for men, and alterations of social reciprocity for women.