Do autism and drug and alcohol syndrome have some of the same symptoms?

My niece was born with a lot of issues. She is four now and we have always thought that she is autistic. She cannot communicate with us but she can talk. She just repeats what she hears. She like things a certain way and gets very upset when her order is disrupted. She throws fits and hurts herself. She has other birth defects that aren't autism. Like a cleft lip and skin tags on her ears and face. She was born with water on the brain and had to have a shunt put in when she was born. She had really slow development. She never really crawled and she didn't walk until she was almost 2. And she is still very weak. My aunt and I took her to get evaluated and the person said that although she has autistic like tendencies, it is most likely drug and alcohol syndrome. We also took her to a geneticist and she said the same thing. People in my family are saying that the doctors are wrong and she has to be autistic. I believe the doctors, but I want to know what you guys think. And I want some iformation to show my family.