My son is 11 years old and just had his first ever chromosomal microarray. it came back as completely normal, but they diagnosed him with autism at 3. how can he be autistic but has a normal chromosomal microarray?

The autism spectrum is composed of a collection of disorders that have similar features. In the past decade, codonal analysis of various parts of the human genome has found more than 100 different "mistakes" encoded in patients who show autistic features. There are many with the same observed features where no errors are detected. Future studies may find more, but for now the MA is not conclusive