Autism Identical Twins Study


We are studying genetic and other differences in identical twins that may be linked to autism. We are looking for families with identical twins (triplets or other multiples are okay, too) where at least one twin has been diagnosed with an autism spectrum disorder. The families will answer questionnaires and provide biological samples for DNA analysis.

Why participate?

Identical twins are a unique population. We think that by comparing twins with and without an autism spectrum disorder, we can learn more about how changes in DNA early in development might contribute to autism.

You may be eligible if:

  • your family contains a set of identical twins (or other identical siblings)
  • at least one twin has been diagnosed with an autism spectrum disorder
  • the twins are at least two years old

What's involved?

  • Answering questionnaires about behavior and development
  • Providing a saliva sample (can be done at home)
  • Providing a blood sample (can be done with your local doctor or at your next clinic visit to OHSU)
  • We are offering $100 to families who complete the study

For more information, please contact us at or 503-494-2971

Principal Investigators: Brian J. O'Roak, Ph.D., and Eric Fombonne, M.D.

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Do I need to travel to OHSU to participate?

No!  We can arrange for biosamples to be collected at a location convenient to you, and forms for the study can be completed by mail or online.

Who is eligible to participate?

Families with identical twin pairs, ages 2 and up, where at least one twin has an autism spectrum disorder diagnosis. Examples of diagnoses could include autism, autistic disorder, autism spectrum disorder (ASD), Asperger Syndrome, Pervasive Developmental Disorder (PDD), or Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS).  If you are curious if you or your children have a qualifying diagnosis, please contact us!  Both biological parents are asked to participate in addition to the twins.

What if I don't know whether my twins are identical (or whether I am an identical twin)?

If you or your children might be part of an identical twin pair with ASD, we would like you to participate.

What if my kids can/will not tolerate a blood draw?

Participation using alternate biosamples may still be possible--please contact us using the form below in order to discuss participation.

We are looking for families with a set of identical twins, where at least one twin has been diagnosed with autism, to participate in a research study.