Living with Tetrasomy 21
An extremely rare chromosome condition with features like Down syndrome, plus some added features.
Understanding Tetrasomy 21
It has many features of trisomy 21, including developmental delay, low muscle tone, a flat face, and short fingers. Other features can include early birth, slow growth before birth, and a high, broad forehead. Blood cancers are also linked to it and may occur earlier than in trisomy 21. It may be noticed during pregnancy, at birth, or in infancy.
Signs & symptoms
Symptoms vary from person to person. GARD lists these among the most common:
- Global developmental delay
- Intellectual disability
- Low muscle tone (hypotonia)
- Small head (microcephaly)
- Round, flat face with upward slanting eyes
- Single crease across the palm
Not everyone has every symptom. GARD's list comes from the Human Phenotype Ontology.
Diagnosis
- 1Talk with your doctor
Share the symptoms you've noticed, when they started and your family health history. Notes and photos can help.
- 2See a specialist
Specialists who may be involved include genetic specialists.
- 3Ask which tests can help
Your care team will decide which exams and tests can confirm the diagnosis.
Care & treatment
- Care team
- Genetic specialists (geneticists)
- Expert care
- Ask about multidisciplinary care centers for rare conditions
- Treatment
- GARD doesn't list specific treatments for this condition. Your care team will tailor care to your symptoms.
- Research
- Clinical trials and observational studies may be options. See the research section below.
General information, not medical advice. Your care team makes the decisions.
Everyday life
Living with a rare condition is easier with support.
- Connect with Chromosome Disorder Outreach
- Keep notes on symptoms, changes and questions for appointments
- Ask about patient registries that help research
- Look into financial aid and travel resources for care visits
Quick facts
Tetrasomy 21 results from having four copies of chromosome 21 instead of two.
Also known as: isochromosome 21; tetrasomy type 21
Patient organizations
- Chromosome Disorder OutreachChromosome disorders · United States
Broader rare-disease groups
- Global GenesRare Diseases · United States
- National Organization for Rare DisordersRare Diseases · United States
- Genetic AllianceRare Diseases · United States
- RARE FoundationRare Diseases · United States
You are more than your diagnosis
Perspectives from people navigating life with Tetrasomy 21.
Explore research for Tetrasomy 21
Explore actively recruiting Tetrasomy 21 studies with HealthSpark.
Find actively recruiting studies for Tetrasomy 21 with HealthSpark. Share your city to explore research near you.
- Recruiting studies from ClinicalTrials.gov
- Share your city to look for research near you
- Eligibility is confirmed by the study team
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Powered by HealthSpark, our AI chat helper · Study information from ClinicalTrials.gov · Eligibility is confirmed by the study team.
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