An executive committee oversees the project. The parameters for DNA sample selection and (genetic and phenotypic) data are managed by the committee, including consenting and ethics protocols. Coded identifiers’ for samples selected for WGS are posted as they are identified at MSSNG portal (http://mss.ng/research), so the ASD research community can monitor progress. Phenome data include subject information (identity number, year of birth, sex), family code (proband, parent, sibling), results of diagnostic tests (e.g. ADOS, ADI-R, age at diagnosis, functional assessments, intelligence tests, body measurements and dysmorphic features). The database accommodates as much of this information as is available for each sample, but that varies widely. Future plans include incorporation of fields for co-morbidities, related conditions, exposures, extended family history, interventions, and other parameters that become apparent. WGS technologies were Complete Genomics and Illumina HiSeq (2000 and X). WGS data are transferred to Google Genomics for data processing through the Google Cloud. Ref-blocked gVCFs were generated and stored in Google Cloud Storage, which were also processed for de novo mutation detection in the local cluster (for Complete Genomics data using filtering method) and Google Compute Engine (for Illumina data using DenovoGear). The Ref-blocked gVCFs and the de novo mutations were annotated through the Google Compute Engine (using Annovar), which can be accessed through the BigQuery tables. Quality controls of the genomic data were performed in the local cluster and the Google Cloud. The processed genetic data and the phenotypic data are accessible through the MSSNG Portal interface. The MSSNG database is designed to support incremental addition of data without changes in architecture, scaling to at least tens of thousands. New WGS and phenotype data are continually added to MSSNG as new batches of 1,000 samples are processed. DACO: Data access committee; UPD: Uniparental disomy; Ti/Tv: Transition to transversion ratio; IBS: Identity by state.