Thousands of microvilli form a structure called the brush border that is found on the apical surface of some epithelial cells, such as the small intestines. (Microvilli should not be confused with intestinal villi, which are made of many cells.
Autism spectrum disorder has no single known cause. Given the complexity of the disorder, and the fact that symptoms and severity vary, there are probably many causes. Both genetics and environment may play a role. 1  Genetic problems. 2  Several different genes appear to be involved in autism spectrum disorder.
In no certain order, I have read the following explanations for autism over the years: Autism is caused by mercury. Autism is caused by lead. Autism begins with poor maternal bonding. Certain pesticides may trigger autism. Plastics. Gluten aggravates autism spectrum disorder. People with autism should eat more strawberries. Too much automotive exhaust is a leading cause of autism. Chemicals found on non-stick cookware may trigger autism.