The coexistence of genetic disorders and environmental events in the etiology of autism spectrum disorders

This study asked the question: is the co-existence of specific inherited neurological disorders and specific environmental events correlated with autism above and beyond the correlation of either factor alone? The specific neurological disorders investigated were; prenatal exposure to teratogens/toxins or viruses, perinatal difficulties, febrile seizures, severe reactions to medications/immunizations, significant exposure to toxins or repeated heavy doses of antibiotics. The specific environmental events investigated were; familial history of autism, Tourette's syndrome, obsessive compulsive disorder, language disorder, ADHD or dyslexia. The study was a correlational field design with a written survey format. The test population for this study included 72 children, ages 3 through 18, with a diagnosis of autism/PDD. The non-autistic population included 117 children with no diagnosis or clinical features of autism/PDD. The children's caregivers completed a questionnaire developed by the researcher. The questionnaire asked if the participating child had autism, a family history of one of the disorders mentioned above and experienced exposure to an identified environmental event. The study found that within the autistic population the presence of an autism spectrum disorder, Tourette's syndrome, behaviors consistent with a diagnosis of Tourette's syndrome, and a family member with behaviors consistent with a diagnosis of ADHD were significant as compared to the non-autistic population. There was not a reported significance in the occurrence of OCD, language disorder, or dyslexia. Of the 12 genetic factors studied one or more was reported in the histories of 68% of the autistic children verses 46% of the non-autistic children and the autistic children had a greater total number of factors overall. Significant scores were obtained by the autistic subjects for prenatal exposure to toxins/teratogens and perinatal difficulties, repeated courses of antibiotics and exposure to mercury. Neither febrile seizures nor severe reactions to immunizations/medications achieved a significant result. A significant difference was noted between the two groups with 83.3% of the families of autistic children reporting at least one environmental factor, compared with 68.4% of the non-autistic families. Environmental factors were tallied for each child, with a mean of 2.22 exposures for the autistic group verses a 1.42 average for children without autism. Finally, a statistically significant chi-square was obtained indicating that autism was more likely to occur in children for whom both a genetic and an environmental factor was present.