Autism is a neuropsychiatric childhood disorder characterized by severe and pervasive impairment in several areas of development such as social interaction skills, communication skills and/or presence of stereotype behavior, interest and activities. The onset is usually within the first three years of life. 
Developmental regression among children with autism is a common phenomenon of unknown origin. Regression in language, social skills and play is usually observed between the first and third years of life. 
There has been an exponential rise in the prevalence of autism over the last 10 years.  Data released from the CDC (Centers for Disease Control and Prevention-national public health institute of the United States of America) in April 2012 placed the prevalence of autism in the U.S. at approximately 1 in 88 children. No data is available from India to provide an India-specific estimate of the prevalence.