There are 1583 disorder (inborn errors of metabolism; IEM) entries, 3679 biochemical or clinical phenotype entries, and 9679 disorder-phenotype association entries in the IEMbase.App features: ICIMD classificationEasy browsing through IEM categoriesSimple search for any IEM or term (clinical, biochemical or genetic)Mini-expert system to search for a combination of clinical symptoms and biochemical markers and their deviationsDifferential diagnosis panelBiochemical tests panelGene panelAge-related clinical symptomsAge-related biochemical markersDisease and gene informationHuman phenotype ontology (HPO) mappingHuman metabolome database (HMD) mappingLinks to Genetic Testing Registry, NCBI Gene, Gene Cards, Uniprot, KEGG, OMIM, OrphaCode and Gene reviewsGamut tablesNosologyWikiPathwaysTreatment module (in development)Expert PanelIEMBase is only a tool to help physicians in the diagnosis of IEMs. Thus, the users should seek a doctor’s advice in addition to using this app and before making any medical decisions.