Autism spectrum disorder (ASD) is a pervasive neuro-developmental disorder with prominent reciprocal social and communication impairment and restricted repetitive behavior or interest. Because ASD runs in family, because there is no effective biological treatment, and because early intervention can lead to better outcomes, ASD has been given a high priority for genetic and neurobiological study. Although abnormal brain structure has been reported, there is limited data regarding structural and functional dysconnectivity in autism. There is no such information in Asian population and no study has conducted using Diffusion Spectrum Imaging (DSI) to investigate the connectivity throughout the world. Moreover, no follow-up study has been done to examine the developmental changes of structural and functional connectivity. We thus propose this prospectively follow-up brain imaging study on ASD.