Synonyms: Trisomy 21
A total autosomal trisomy that is caused by the presence of a third (partial or total) copy of chromosome 21 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 neurosensorial or endocrine defects.
Data from Orphanet are used to provide information on a disease's name, synonym(s), and overview. Reference: Access aggregated data from Orphanet at Orphadata. Orphadata: Free access data from Orphanet. © INSERM 1999. Available on http://www.orphadata.org. Data version April 2026
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Down syndrome?
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Advocacy Organizations
Heart of a Giant Foundation
The mission of the HGF is to achieve better health outcomes for heart diseases and related chronic health conditions in our communities and enhance the quality of life through health education, care support, and connection to community resources.
PPP2CA Pathways
PPP2CA Pathways connects families, shares strength, and supports the research community in the search for answers to Houge-Janssens Syndrome type 3.
Pakistan Down Syndrome Association (PDSA)
VISION To promote an inclusive & accessible society in which everybody including poor, marginalized and disadvantaged communities have to entertain equal opportunities and facilities MISSION To improve quality of life for people with Rare Diseases in Pakistan and promote their inherent right to be accepted and included as valued and equal members of their communities.
Rare Chromosome Disorder Support Group – Unique
Through sharing knowledge and lived experience, Unique helps families and professionals navigate the world of chromosome and gene disorders
RareDNA Foundation
Dedicated to improving outcomes for individuals and families affected by rare DNA heart mutations by advancing awareness, access and action. We increase awareness among medical professionals and the public, provide education and resources on diagnosis and treatment, support scientific research, and advocate for faster diagnostic pathways, giving families the knowledge and care they need.
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Clinical Trials
For a list of clinical trials in this disease area, please click here.