The research in Jiang’s lab is directed at understanding genetic and epigenetic basis of human diseases with a focus on genomic imprinting disorders of Angelman and Prader-Willi syndrome as well as autism spectrum disorders. Angelman syndrome and Prader-Willi syndrome are two best examples of genomic imprinting disorders caused by the defect of an imprinting domain in the human chromosome 15q11-q13 region. Autism spectrum disorders are neurodevelopmental disorder that affects 1 out 160 children. The core symptoms of autism spectrum disorders are impairment in communication and language development, social interaction, and stereotyped behaviors. Although the strong genetic etiology is implicated in autism spectrum disorders, the molecular basis for majority of individuals with autism spectrum disorders remains unknown. From lessons learned from genomic imprinting disorder of Angelman syndrome, we hypothesize that both genetic and epigenetic defects in genes encoding synaptic proteins contribute to the susceptibility of autism spectrum disorders.