Autism and autism spectrum disorders (ASD) affects the areas of social awareness and interaction, verbal and nonverbal communication, and behaviors and interests, which are grouped among neurobehavioral disorders. One in 68 children is affected with ASD according to the estimate from the Center for Disease Control and Prevention's autism and developmental disabilities monitoring network and an increasing prevalence observed worldwide. A characteristic heterogeneity in ASD determined genetic variability as a major contributor. Whole-exome sequencing of ASD individuals revealed that discrete de novo mutation (single-nucleotide variation or small indels) also contribute to the overall genetic risk of ASD apart from rare genetic variation affecting single nucleotides of protein-coding DNA or rare genomic copy number variants as assessed through other high-throughput genomic methods. These genes are involved in synaptic transmission and regulated during brain development by acting upstream or downstream of Wingless- related integration site (WNT), bone morphogenetic proteins/transforming growth factor-β, sonic hedgehog, fibroblast growth factor, and retinoic acid signaling pathways. The current review focuses on genes involved in synaptic function, undergoing de novo mutation leading to ASD condition.