Autism Spectrum Disorder (ASD) is a developmental disorder diagnosed at a young age that causes disabilities in social communication skills and behavioral challenges. The three types of ASD are autism, Asperger's syndrome, and pervasive developmental disorder. Symptoms include unusual body language, avoiding eye contact, lack of interest in social interaction, and difficulty understanding other people's feelings. There is no known cure for ASD, but medications can help treat related symptoms like seizures or inability to focus. The causes are unknown but believed to involve a combination of genes and environmental factors influencing early brain development.