The goal of this study is to validate a panel of miRNAs that distinguish children with autism spectrum disorder (ASD) from their non-ASD peers with a positive MCHAT-R. These biomarkers may allow earlier diagnosis of autism, allowing earlier service, and also help us to understand some of the changes in the brains of autistic children.

The central aim of this project is to validate a panel of expressed microRNA (miRNA) in the saliva of children identified at risk for developing ASD by the MCHAT-R. Further, this study aims to assess the value of the current panel as an adjunctive test that may increase specificity of MCHAT-R positive results, or affirm clinical diagnoses alongside the ADOS or other objective assessments.

The primary endpoints of this study are as follows:

1. Evaluate the diagnostic ability (sensitivity and specificity) of the current a salivary microtranscriptome panel for distinguishing children with ASD from their non-ASD peers.
2. Assess stability of the salivary microtranscriptome diagnosis over time, and interrogate longitudinal microtranscriptome levels relative to neuropsychological measures.

Secondary endpoints are the identification of microtranscriptome features whose concentrations correlate with ASD endophenotypes.

Inclusion Criteria:

• Age at enrollment: 24 months to 48 months (inclusive)
• MCHAT-R score of 3 or greater
• Parent/guardian must be fluent in spoken English (required to complete study specific questionnaires etc)

Exclusion Criteria:

• confounding neurological (i.e. cerebral palsy, epilepsy), sensory (i.e. auditory or visual) impairments, and feeding tube dependence.
• history of extreme pre-term birth (< 32 weeks gestation)
• wards of the state
• Autistic subjects with known syndromic autism (attributed to a known genetic mutation)

The study will compare salivary miRNA in children between the ages of 24 months and 48 months of age who are considered at risk for the development of autism spectrum disorder as identified by a score of 3 or greater on the MCHAT-R.