Hello.
There are some reports (case reports) of a common link between Multiple Sclerosis and Autism, but there is no conclusive evidence to it yet. The common link is believed by some to be on chromosome 6, while one researcher reports of a newly identified virus to be a common factor between various immune system dysfunctions including MS and autism.
It is true both these conditions are concerned with the central nervous system, but I'm afraid we do not have sufficient data to prove any association yet.
Autism has been associated with Tuberous Sclerosis, but there is not conclusive evidence about MS. Tuberous Sclerosis is not quite similar to MS.
Multiple Sclerosis involves a degeneration of the coverings of the nerve cells, leaving them exposed and unprotected, eventually leading to damage. Autism is a developmental disorder of the nerve cells and the connections among them. There is faulty pattern of connections that create the problems seen in autism.
Hope this helps a bit.
Abhijeet Deshmukh, MD
(This post is for the purpose of providing medical information and is not a substitute for a face-to-face consultation with a doctor. This post is not intended to give or rule out a diagnosis, create a doctor-patient relationship or replace an existing one. I am not able to diagnose medical conditions online. Please consult with your doctor or a qualified healthcare provider for diagnosis and treatment options)