Descriptive Analysis of 252 Twin Sets Recruited Through a National Online ASD Registry and Research Database

Background: Twin studies provide an opportunity for researchers to disentangle genetic and environmental factors related to Autism Spectrum Disorders (ASD). Multiple twin studies report much higher concordance rates for monozygotic (MZ) twins compared to dizygotic (DZ) twins, supporting a strong genetic component to the disorder.  The small sample size in twin studies, however, limits further exploration of many research questions.  Recruitment of twin sets continues to be a challenge for autism researchers.

Objectives: To present baseline characteristics, demographics and other preliminary analysis on 252 twin sets enrolled in the Interactive Autism Network (IAN) research registry and database.

Methods: IAN is an initiative intended to accelerate autism research through an online registry and research database.  Questionnaires are used to collect data from families, including the child with ASD, unaffected siblings and biological/adoptive parents.  More than 20,000 individuals are enrolled. The database is an open resource, providing de-identified data and recruitment assistance to autism researchers. 

Results: In less than 9 months, 252 twin sets (55 MZ and 197 DZ) enrolled in the IAN research protocol.  This is the largest collection of twins in published autism research.  Basic demographics such as age, gender, race, and ethnicity will be presented. Similar to other published findings, concordance rates are 81% for MZ and 18% for DZ twins. Preliminary analysis shows that gender does not predict concordance in either MZ or DZ twins.  Concordance rates were not affected by age of twins.  Among all twin sets, only 6.8% reported prior genetics research participation.

Conclusions: This study demonstrates successful recruitment of an unprecedented number of twin sets in a short time using internet-mediated research.  A large number of twin sets are required to explore the complex genetic and non-genetic factors contributing to ASD.  Future use of this database by autism researchers will demonstrate the long-term value of the resource.