Austim in-depth

One has to understand that ASD or autism is a chronic condition.
This is just a general idea of what causes ASD, experts are still uncertain about all the causes of autism.
There are multiple causes rather than just one. It appears to be that a number of different of different circumstances that include environmental, biological and genetic factors- set the stage for autism and make a child more likely to have the disorder.

So after all is said and done nobody actually knows what causes ASD.
There are also other disorders that are associated with autism.
In my brother's case an associated condition is ADHD-Attention Deficit Hyperactivity Disorder.

Some of the most common Symptoms which are usually apparent when the child grows are the following:
Behavioural: inappropriate social interaction, poor eye contact,compulsive behaviour, impulsive, repetitive movements( My brother rocks back and forth), self-harm, persistent repetition of words or action just to mention a few.
Developmental: Learning disability or delayed speech.
Psychology: Unaware of other's emotions, Anxiety- for instance my brother becomes severely frustrated when he is around a large number of people and whenever his routine has been changed, sensitivity to sound.

Sources: Mayo Clinic and MyChildwithoutlimit.org
Link: www.mychildwithoutlimits.org/understand/what-causes-autism