The purpose of this study is to characterize the developmental phenotype of ASD and ID and to identify biomarkers using advanced MRI methodology and electrophysiological biomarkers of synaptic function and connectivity predictive of ASD and ID presence and severity in patients with TSC. In addition, this study will be establishing infrastructure for the collection and storage of human bio-specimens, including genetic material, from TSC patients and their family members with ASD.

Tuberous Sclerosis Complex (TSC) is a multi-system disease that usually exhibits a high variability in clinical findings both among and within families. About 50% of individuals with TSC develop intellectual disability (ID) and/or autism spectrum disorder (ASD). The purpose of this research study is to learn more information about ASD/ID in individuals with TSC through neurobehavioral assessments, electroencephalogram (EEG) data, and magnetic resonance imaging so that ultimately effective treatments and interventions for ASD/ID can be realized.

Individuals with TSC will be asked to participate in this study if they are 18 months or older at the time of enrollment and have been diagnosed with suspected or confirmed autism spectrum disorder and/or intellectual disability, as well as healthy controls. Both males and females will be asked to participate. Additionally, to be eligible for study participation, individuals' primary communicative language must be English. The participant and at least one biological parent will be asked to provide biological specimens including DNA and RNA for inclusion in the TSC RDCRN Biorepository.

The study involves 3 on site visits over the course of two years. Study visits will vary in length from about 4 hours to 6 hours. Study visits involve a physical exam, medical history questions, and neuropsychological assessments. A subset of participants between the ages of 2 and 11 years old will take part in the EEG portion of the study. At one point during the study, a blood draw will be done for future research studies. Individuals who have a clinically indicated MRI will have an option to provide routine clinical scans for analysis.

Inclusion Criteria:

• Meets genetic or clinical diagnostic criteria for TSC (Tuberous Sclerosis), the latter based on current recommendations for diagnostic evaluation, such as physical exam, neuroimaging, and echocardiogram.
• Age criteria: over 18 months of age at time of enrollment.
• Is diagnosed or suspected to have ASD and/or ID.
• Primary communicative language is English

Exclusion Criteria:

• Has taken an investigational drug as part of another research study, within 30 days prior to study enrollment.
• For subjects involved in imaging biomarker assessment: contraindications to 3T MRI scanning, such as metal implants/non-compatible medical devices or medical conditions, including vagus nerve stimulator.
• For subjects involved in EEG/ERP biomarker assessment: contraindications to EEG/ERP, such as uncooperative or destructive behaviors preventing lead placement or capture by ERP/VEP equipment. Under age 2 or above age 11 at the time of enrollment.
• Unwilling or unable to comply with study procedures and assessments.

A total of 195 participants over the age of 18 months old with TSC and suspected or diagnosed ASD, ID, or combined ASD/ID will be enrolled into the study. Diagnosis of TSC will be based on established clinical or genetic criteria. Subjects will be enrolled from current and new TSC patients at each of the 6 centers.