Living with Monosomy 21
A chromosome condition with developmental delay, intellectual disability, behavior concerns, and distinctive facial features.
Understanding Monosomy 21
The signs depend on the size and location of the missing piece and which genes are involved. Features that often occur include developmental delay, intellectual disability, behavior problems, and distinctive facial features. Most cases are not inherited, but people can pass the deletion on to their children.
Signs & symptoms
Symptoms vary from person to person. GARD lists these among the most common:
- Delays in reaching developmental milestones
- Intellectual disability
- Slow growth before and after birth
- Hole between the upper heart chambers (atrial septal defect)
- Low blood counts (anemia, low platelets)
- Repeated infections
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 eye disease specialists and genetic specialists.
- 3Ask which tests can help
Your care team will decide which exams and tests can confirm the diagnosis.
Care & treatment
- Care team
- Eye disease specialists (ophthalmologists); 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
This condition is caused by a missing copy of genetic material on the long arm of chromosome 21. GARD says most cases are not inherited, but people can pass the deletion on to their children.
Also known as: 21q deletion syndrome; 21q- syndrome; monosomy type 21; partial 21q monosomy
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 Monosomy 21.
Explore research for Monosomy 21
Explore actively recruiting Monosomy 21 studies with HealthSpark.
Find actively recruiting studies for Monosomy 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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