My child has symptoms similar to those associated with autism, but it is something else?

Yes: Fragile x, prader willi syndrome, smith-lemli-optiz syndrome and tuberous sclerosis can all mimic autism.

Absolutely: There are a number of disorders that can superficially look like autism, especially in young children. These include language disorders, something called stereotypic movement disorder, simple shyness, intellectual disability (mental retardation), and deafness, to name a few. It can even include children who are developing perfectly normally, just at a different pace than others expect.

Conditions that have: Significant language delays are intellectual disability & developmental receptive/expressive language disorder. Children with tourette syndrome, adhd, fetal alcohol spectrum disorders, non/verbal ld's & juvenile-onset bipolar disorder have impaired executive functions & prosocial/coping skills. None of these has core symptoms of autism: lack of theory of mind, face recognition & joint attention.