Thats a long link...

The study is Biological versus Environmental Factors:
Determining the Cause of Pervasive Developmental Disorders in Children by Jami Zaretsky
Lehigh University
Interesting reading but whats also is interesting is in Chiari one osteoporosis may lead to the development of CM and also reading about rickets.
Rickets can too.

http://www.springerlink.com/content/2gj3d71gjk4g8hlu/

Plus read someone mention Arthritis too..