DO_rare_slim DO_FlyBase_slim NCIthesaurus has material basis in chromosomal duplication syndrome Down syndrome A chromosomal disease that is characterized by flat-looking facial features and weak muscle tone (hypotonia) in infancy and is caused by trisomy of all or a critical portion of chromosome 21 and is associated with intellectual disability. SNOMEDCT_US_2025_09_01:157019002 disease_ontology ORDO:870 MIM:190685 MESH:D004314 NCI:C2993 DOID:14250 Complete trisomy 21 syndrome Down's syndrome Down's syndrome - trisomy 21 Downs syndrome G Trisomy GARD:10247 UMLS_CUI:C0013080 ICD10CM:Q90 ICD9CM:758.0 OMIM mapping confirmed by DO. [SN]. trisomy 21 syndrome chromosome duplication