Overview
Patella aplasia or hypoplasia, bilateral, refers to a condition where both kneecaps (patellae) are either completely absent (aplasia) or underdeveloped (hypoplasia). The patella is the small, flat bone that sits in front of the knee joint and plays an important role in protecting the knee and helping with leg movement. When the kneecaps are missing or smaller than normal on both sides, it can affect how well the knees work and may cause difficulty with walking, running, or climbing stairs. This term is listed as 'OBSOLETE' in Orphanet, meaning it is no longer used as a standalone diagnosis. This is because bilateral patella aplasia or hypoplasia is now recognized as a feature that occurs within several broader genetic syndromes rather than being classified as its own separate disease. Conditions that commonly include absent or small kneecaps include nail-patella syndrome, small patella syndrome (ischiocoxopodopatellar syndrome), and Meier-Gorlin syndrome, among others. If you or your child has been found to have absent or underdeveloped kneecaps on both sides, your doctor will likely look for other associated features to determine which specific syndrome may be responsible. Treatment depends on the underlying condition and the degree of knee problems. Options may include physical therapy to strengthen the muscles around the knee, bracing, pain management, and in some cases surgery to improve knee function and stability.
Key symptoms:
Absent kneecaps on both sidesUnderdeveloped or small kneecapsKnee instability or feeling that the knee gives wayDifficulty walking or runningKnee pain or discomfortLimited range of motion in the kneesDifficulty climbing stairsFrequent falls or trippingSwelling around the knee jointAbnormal gait or walking pattern
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: Patella aplasia/hypoplasia, bilateral.
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Specialists
View all specialists →No specialists are currently listed for OBSOLETE: Patella aplasia/hypoplasia, bilateral.
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: Patella aplasia/hypoplasia, bilateral.
Community
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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.Is my child's absent or small kneecaps part of a broader genetic syndrome?,What genetic testing do you recommend to find the underlying cause?,What physical therapy exercises would be most helpful for knee stability?,Are there other organs or body systems we should be screening?,Will my child need surgery, and if so, at what age is it typically recommended?,What activities should we encourage or avoid to protect the knees?,Is this condition inherited, and should other family members be tested?
Common questions about OBSOLETE: Patella aplasia/hypoplasia, bilateral
What is OBSOLETE: Patella aplasia/hypoplasia, bilateral?
Patella aplasia or hypoplasia, bilateral, refers to a condition where both kneecaps (patellae) are either completely absent (aplasia) or underdeveloped (hypoplasia). The patella is the small, flat bone that sits in front of the knee joint and plays an important role in protecting the knee and helping with leg movement. When the kneecaps are missing or smaller than normal on both sides, it can affect how well the knees work and may cause difficulty with walking, running, or climbing stairs. This term is listed as 'OBSOLETE' in Orphanet, meaning it is no longer used as a standalone diagnosis. T
At what age does OBSOLETE: Patella aplasia/hypoplasia, bilateral typically begin?
Typical onset of OBSOLETE: Patella aplasia/hypoplasia, bilateral is neonatal. Age of onset can vary across affected individuals.