Skip to content
knowrare
HealthSignal
Your condition community

Living with Patella aplasia/hypoplasia

An extremely rare inherited condition in which the kneecap is missing or very small from birth.

Understanding Patella aplasia/hypoplasia

Patella aplasia/hypoplasia is an extremely rare genetic condition in which the kneecap (patella) is absent or much smaller than usual.

It is present from birth. GARD says it has been described in only a few families so far. Signs are noticed in newborns and infants.

Signs & symptoms

GARD doesn't list specific symptoms for this condition yet.

Not everyone has every symptom. GARD's list comes from the Human Phenotype Ontology.

Diagnosis

  1. Talk with your doctor

    Share the symptoms you've noticed, when they started and your family health history. Notes and photos can help.

  2. See a specialist

    Specialists who may be involved include bone and joint specialists and genetic specialists.

  3. Ask which tests can help

    Your care team will decide which exams and tests can confirm the diagnosis.

Care & treatment

Care team
Bone and joint specialists (orthopedists or orthopedic surgeons); 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 rare disease patient organizations for support
  • 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
Bring these questions to your next doctor visit
How does a missing or small kneecap affect walking and knee use?
Which bone specialists should see my child?
Would genetic testing help our family?

Quick facts

Symptoms usually startNewborn and as an Infant
InheritanceAutosomal Dominant

Changes in the genes (also called variants) cause this condition. It is autosomal dominant, which means one changed copy of the gene is enough to cause it.

Genetic

Also known as: absent or hypoplastic patellae; absent/hypoplastic patella; absent/small kneecap; absent/underdeveloped kneecap; aplasia/hypoplasia of the patella; aplastic or hypoplastic patellae

Patient organizations

Rare-disease groups that can help

Source: NIH GARD · Patella aplasia/hypoplasiaGARD ID 8709 · GARD page updated September 2026 · Plain-language summary by Know Rare; editorial review pending. General information, not medical advice.

You are more than your diagnosis

Perspectives from people navigating life with Patella aplasia/hypoplasia.

Explore the Patella aplasia/hypoplasia blog

Explore research for Patella aplasia/hypoplasia

Explore actively recruiting Patella aplasia/hypoplasia studies with HealthSpark.

HealthSpark

Find actively recruiting studies for Patella aplasia/hypoplasia 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

Powered by HealthSpark, our AI chat helper

I can help you find recruiting Patella aplasia/hypoplasia studies. Enter a ZIP code, address or city below and I'll look within 50 miles.

Powered by HealthSpark, our AI chat helper · Study information from ClinicalTrials.gov · Eligibility is confirmed by the study team.

Get Signals for Patella aplasia/hypoplasia

Stay in the loop with community stories and updates from medical researchers.

HealthStoryfor Patella aplasia/hypoplasia

Create a living journal that talks back

HealthStory evolves private journaling with a living AI journal that talks back and asks thoughtful questions, helping you capture your Patella aplasia/hypoplasia experiences more deeply and prepare for better conversations with your doctors and care team.

Start your journal

Your journal is private. Sharing your story publicly is a separate choice, made with Share your story above.