Overview
The term 'Anomaly of chromosome 21' is an obsolete (no longer actively used) classification that was previously used to describe a range of structural or numerical changes involving chromosome 21. Chromosome 21 is the smallest human chromosome, and changes to it can lead to various health conditions. The most well-known condition linked to chromosome 21 is Down syndrome (trisomy 21), where there is an extra copy of this chromosome. However, this obsolete category also encompassed other rearrangements such as partial deletions, duplications, ring chromosomes, or translocations involving chromosome 21. Because this is no longer a current diagnostic term, patients who were previously classified under this label may now have more specific diagnoses based on modern genetic testing. The symptoms and severity depend entirely on the type and extent of the chromosome 21 change. Common features across many chromosome 21 anomalies can include intellectual disability, distinctive facial features, heart defects, growth delays, and developmental differences. Treatment is tailored to the specific condition and symptoms present, and may include early intervention therapies, surgical correction of heart or other organ defects, educational support, and ongoing medical monitoring. If you or a family member has been given this diagnosis, it is important to seek updated genetic evaluation to obtain a more precise diagnosis, which can guide treatment and prognosis more accurately.
Key symptoms:
Intellectual disability or learning difficultiesDelayed speech and language developmentDistinctive facial featuresLow muscle tone (floppiness in babies)Heart defects present at birthShort stature or growth delaysDelayed motor milestones like sitting and walkingHearing problemsVision problemsDigestive issuesThyroid problemsIncreased risk of infectionsBehavioral differences
Variable
Can be inherited in different ways depending on the underlying gene
Neonatal
Begins at or shortly after birth (first 4 weeks)
Treatments
No FDA-approved treatments are currently listed for OBSOLETE: Anomaly of chromosome 21.
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Specialists
View all specialists →No specialists are currently listed for OBSOLETE: Anomaly of chromosome 21.
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to OBSOLETE: Anomaly of chromosome 21.
Community
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Caregiver Resources
NORD Caregiver Resources
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Mental Health Support
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Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What is the exact type of chromosome 21 change my child has, and what does it mean?,Should we get updated genetic testing such as chromosomal microarray for a more precise diagnosis?,What early intervention services should we start, and how soon?,Does my child need a heart evaluation or other organ screening?,What is the expected developmental outlook for my child's specific condition?,Are there any clinical trials or new treatments being studied that might be relevant?,What is the chance of this happening again in a future pregnancy?
Common questions about OBSOLETE: Anomaly of chromosome 21
What is OBSOLETE: Anomaly of chromosome 21?
The term 'Anomaly of chromosome 21' is an obsolete (no longer actively used) classification that was previously used to describe a range of structural or numerical changes involving chromosome 21. Chromosome 21 is the smallest human chromosome, and changes to it can lead to various health conditions. The most well-known condition linked to chromosome 21 is Down syndrome (trisomy 21), where there is an extra copy of this chromosome. However, this obsolete category also encompassed other rearrangements such as partial deletions, duplications, ring chromosomes, or translocations involving chromos
At what age does OBSOLETE: Anomaly of chromosome 21 typically begin?
Typical onset of OBSOLETE: Anomaly of chromosome 21 is neonatal. Age of onset can vary across affected individuals.