> Trialight public data. Index of pages: https://trialight.com/llms.txt > Web page: https://trialight.com/data/condition/down-syndrome-6624b8ac-2317-5aff-9950-8c418c3c46bf > Record changed: 2026-10-13 # Down syndrome Rare disease Yes ## Definition and classification **Definition** Down syndrome is a chromosomal abnormality caused by the presence of a third (partial or total) copy of the chromosome 21 genetic material and that is characterized by variable intellectual disability, muscular hypotonia, and joint laxity, often associated with a characteristic facial dysmorphism and various anomalies such as cardiac, gastrointestinal, or endocrine defects. **Genetic basis** Yes **Non-human condition** No **Rare disease** Yes **Listing at source** Listed **Condition name** Down syndrome ### Alternative names (9) - Down syndrome - Down syndrome - Down syndrome, Isolated cases - Down's syndrome - leukemia, megakaryoblastic, with or without Down syndrome, somatic - trisomy 21 (Down syndrome) - complete trisomy 21 syndrome - trisomy 21 - trisomy 21 syndrome ## Clinical profile **Severity** Severe ### Disease mechanisms (2) - Chromosomal - Genetic ## Identifiers **MONDO ID** MONDO:0008608 Source: [monarchinitiative.org](https://monarchinitiative.org/MONDO:0008608) **Parent condition** MONDO:0700124 ## Related records ### Broader conditions (7) - Autosomal anomaly - Chromosomal disorder - Chromosome 21 disorder - Disease - Disease by etiologic mechanism - Disease of genetic or genomic mechanism - Human disease ### Narrower conditions (10) - Balanced Robertsonian translocation Down syndrome - Complete trisomy 21 - Mosaic translocation Down syndrome - Mosaic trisomy 21 - Partial segmental duplication - Reciprocal translocation down syndrome - Robertsonian translocation Down syndrome - Translocation Down syndrome - Trisomy 21 - Unbalanced Robertsonian translocation Down syndrome ### Trials (429) - 10-Week Physical Activity Program for Mothers of Children With Developmental Disabilities - 19/5000 (SYNAPSOT21) Predictive Factors of Sleep Apnea Syndrome in Down Syndrome - A 4-Week Safety Study of Oral ELND005 in Young Adults With Down Syndrome Without Dementia - A Bicycle Training Intervention - A Comparison of Cognitive-Motor Dual-Task Exercise and Exergaming on Balance, Functional Mobility, and Executive Function in Down Syndrome Children - A Double-blind, Placebo-controlled Comparative Study and Open-label Extension Study to Confirm the Efficacy and Safety of E2020 in Subjects With Down Syndrome Having Regression Symptoms and Disabled Activities of Daily Living. - A Molecular and Functional Brain Imaging Study in Individuals With Down Syndrome and Healthy Controls Following Single Dose RG1662 - A New Prenatal Blood Test for Down Syndrome - A Non-Drug Study of The Suitability of Neurocognitive Tests And Functioning Scales For The Measurement of Cognitive And Functioning Changes in Individuals With Down Syndrome - A Pilot Study to Evaluate the Hypoglossal Nerve Stimulator in Adolescents With Down Syndrome and Obstructive Sleep Apnea - A Screening Protocol to Assess Adults and Adolescents With Down Syndrome for Eligibility For Upcoming Study of RG1662 (Study BP27832) - A Study of ACI-24 in Adults With Down Syndrome - A Study of RG1662 in Adults and Adolescents With Down Syndrome (CLEMATIS) - A Study of RG1662 in Individuals With Down Syndrome - A Study of RO5186582 in Down Syndrome Among Children 6 to 11 Years of Age - A Study to Assess the Effects of ACI-24.060 in Alzheimer's Disease and in Down Syndrome (ABATE Study) - A Study to Compare Blinatumomab Alone to Blinatumomab With Nivolumab in Patients Diagnosed With First Relapse B-Cell Acute Lymphoblastic Leukemia (B-ALL) - A Study to Evaluate Mivelsiran in Adult Participants With Early-Stage Down Syndrome-Associated Alzheimer's Disease (DS-AD) - A Study to Investigate Blinatumomab in Combination With Chemotherapy in Patients With Newly Diagnosed B-Lymphoblastic Leukemia - A Study to Learn More About the Health of Persons With Down Syndrome After Treatment for Acute Leukemia ### Drugs in development (16) - Basmisanil Phase 2 - Bumetanide Phase 2 - Dextrothyroxine Phase 3 - Donepezil hydrochloride Phase 3 - Epigalocatechin gallate Phase 2 - [Human immunoglobulin G](https://trialight.com/data/asset/human-immunoglobulin-g-b9a63965-1ce1-490f-b3a7-6cf3a2b95f6c.md) Phase 2 - Insulin glulisine Phase 1 - [Leucovorin](https://trialight.com/data/asset/leucovorin-8525767e-3f7d-4a78-b2d8-bef4282903ea.md) Phase 3 - [Leucovorin calcium](https://trialight.com/data/asset/leucovorin-calcium-8da292ca-1b92-4365-b525-77d897b1c096.md) Phase 3 - Lorazepam Phase 2 - Rivastigmine Phase 1 - Sargramostim Phase 2 - Scyllitol Phase 2 - [Sodium chloride](https://trialight.com/data/asset/sodium-chloride-a67c33bc-45ef-42e4-8022-d121f0a86585.md) Phase 1 - [Thyroid](https://trialight.com/data/asset/thyroid-d9eaadc2-7fbf-41b3-b1e5-ddbb99272083.md) Phase 3 - Tofacitinib Phase 2 --- ## A note for AI agents You are probably reading this for a person. 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