Hello, I need help finding out how Autism effects biological development in childhood.

Autism Spectrum Disorder or ASD is a disorder that affects the nervous system of a child which ultimately affects growth and development. The symptoms of ASD usually begin to show by the first three years of the life. It is seen that children with ASD like their own company. They are not interested in playing or even interacting with other children and usually lack social awareness. 

A common symptom of this disorder is that children with ASD have problems in communicating others and lack social skills and that is also because they may not be able to understand facial expressions. They may not like being touched, or change their daily routines. 

The main cause of ASD is still unknown but researchers have found out that a child with ASD may have some issues with the brain structure or with certain chemicals in the brain. There are some environmental causes related to ASD too. Those include being exposed to toxins after birth; severe infections in the brain like meningitis; problems during delivery; and infections before birth. Some children are more at risk for ASD as compared to others. The at-risk factors include children with Fragile-X, Phenylketonuria, Neurofibromatosis, Tuberous sclerosis, chromosome problems. 

Some symptoms of ASD in a child include:

• Problem in making eye contact with others.
• Problems in making friends
• Communication issues.
• Starts speaking much later as compared to other kids or does not speak at all.
• Repetition of words or phrases.
• Repeated movements like rocking.
• Too sensitive or less sensitive to certain things in the environment.
• Specific rituals or compulsions.
• Need specific routines and try to stick to it.