 Concept-Style Query NDA has predefined ontological concepts that can be used to query all NDA and federated data. One selects a Concept and applies the filter to see the number of subjects available. Those that have access (NDA Credentials) may then download any datasets. The NDA has adopted the published Autism Spectrum Disorder (ASD) phenotype ontology, defined in "Modeling the Autism Spectrum Disorder Phenotype" as an initial implementation of ontological concepts. 