Autism is a pervasive neurological disorder that is noticeable in early childhood and extends throughout the lifespan, characterized by language development, atypical communication, eye contact, and sensory experiences. This lifelong developmental condition is also known as an autism spectrum disorder.
While some researches affirmed that genetic factor is one of the causes of autism, there are, however, other causes of this condition that are yet to be identified. Down syndrome, on the other hand, is a medical condition that makes a patient share a certain resemblance to the Mongoloid race. According to researches, down syndrome is caused by a chromosomal excess, which in turn causes a delay in the cognitive function and ability of the patient, certain characteristic facial features, small stature, etc.
The common types of autism are Asperger Syndrome, classic autism, atypical autism. The common types of down syndrome are Mosaic Down syndrome, Trisomy 21, Robertsonian translocation. While there's no known cause of autism, down syndrome is caused by a chromosomal excess, usually a product of abnormal cell division.