Autism spectrum disorder (ASD) is characterized by repetitive behaviors and restricted patterns in actions, play, food, and clothing. Language difficulties, including limited or absent speech and poor social interaction, are common. Some individuals with ASD may have speech but struggle with using it for social communication. ASD is a developmental disorder stemming from differences in brain development, although the precise cause is unknown. Risk factors include family history, advanced parental age, genetic mutations, and birth complications.