Grant: CIHR Fellowship

Turner syndrome (TS) is a complex genetic disorder associated with complete or partial monosomy of the X chromosome and is one of the most common sex chromosome abnormalities, affecting 1/2000 live born females. Individuals with TS present a particular cognitive profile, among which social impairments are prominent. While the cognitive profile of TS is reasonably well understood, the neural underpinnings of this profile are only beginning to emerge. Namely, functional and structural abnormalities documented in TS have been suggested to contribute to the cognitive profile observed in this population. Interestingly, these neuroanatomic and cognitive- behavioral outcomes in TS may be influenced by epigenetic factors in the form of genomic imprinting, a process by which certain genes are expressed in a parent-of-origin-specific manner. Indeed, TS who retain the paternal (Xp) X chromosome seems to show less cognitive deficits than individuals with an X from maternal origins (Xm). The specific aims of this study are designed to examine the gene-brain-behavior associations in a large, pre-estrogen TS cohort. The two main objectives are (1) to elucidate the neuroanatomical/functional substrates of face/emotion processing impairments in TS; and (2) to characterize neuroanatomical and brain function differences in Xm and Xp girls. Establishing the neural underpinnings of cognitive deficits in TS, as well as their developmental course, will greatly improve our understanding of the pathogenesis of the TS phenotype and provide a foundation for the development of specific and effective interventions. Moreover, potential differences between girls with Xp and Xm in brain and cognitive/behavioral function will provide important clues for targeting individuals in particular need of social, behavioral, educational or pharmacological interventions early in development.