Autism causes

There have been many proposed genetic and environmental causes of autism but evidence is still incomplete. There is currently no single, or identifiable cause of Autism. Some researchers believe that because autism is not a single disorder, but rather a few core aspects: social difficulties, communication impairments, and repetitive behavior is why there has been no single cause of autism found.

Genetic factors are the highest significant cause of autism. Families with one autistic child have a 5% chance of having another child with the disorder. Some cases have shown that relatives of autistic children show impairments and mild symptoms of autism.

Children with autism symptoms also have a higher than normal risk of having:

Fragile X syndrome, which causes mental retardation
Tuberous sclerosis, in which tumors grow in the brain
Tourette's syndrome
Epilepsy

Other possible causes or contributors to autism include gastrointestinal or immune system abnormalities, allergies, exposure of children to drugs, vaccines, infection, certain foods, or heavy metals. The evidence of these possible causes and factors are anecdotal and have not been confirmed by reliable studies.