Overview
Hyaluronidase deficiency, also known as mucopolysaccharidosis type IX (MPS IX), is a very rare inherited condition where the body cannot properly break down a substance called hyaluronan (also called hyaluronic acid). Hyaluronan is a natural sugar-based molecule found throughout the body, especially in joints, skin, and connective tissue. When the enzyme hyaluronidase does not work properly, hyaluronan builds up in tissues and causes damage over time. This condition belongs to a group of diseases called mucopolysaccharidoses (MPS disorders) or lysosomal storage disorders. The most noticeable features of MPS IX include soft tissue masses (lumps) around joints, short stature, and mild facial changes. Unlike some other MPS disorders, intellectual development is usually normal or near-normal. Joint pain and swelling can make movement uncomfortable. The condition tends to become apparent in childhood, though the full range of symptoms is still being studied because so few cases have been reported worldwide. There is currently no approved cure or enzyme replacement therapy specifically for MPS IX. Treatment focuses on managing symptoms, such as pain relief, physical therapy to maintain joint function, and surgical removal of troublesome tissue masses when needed. Because this disease is extremely rare, most of what is known comes from a very small number of reported patients, and research is ongoing.
Key symptoms:
Soft lumps or masses around joints (especially knees and hips)Short stature (being shorter than expected for age)Mild changes in facial features such as a slightly flattened nose bridgeJoint pain and swellingStiffness in jointsDifficulty with movement due to joint problemsMild enlargement of soft tissuesNormal or near-normal intelligence
Clinical phenotype terms (2)— hover any for plain English
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Childhood
Begins in childhood, roughly ages 1 to 12
FDA & Trial Timeline
1 eventViiV Healthcare — PHASE1
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Hyaluronidase deficiency.
View clinical trials →Clinical Trials
View all trials with filters →No actively recruiting trials found for Hyaluronidase deficiency at this time.
New trials open frequently. Follow this disease to get notified.
Specialists
View all specialists →No specialists are currently listed for Hyaluronidase deficiency.
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 Hyaluronidase deficiency.
Community
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Start the conversation →Latest news about Hyaluronidase deficiency
Disease timeline:
New recruiting trial: A Study to Investigate Pharmacokinetics, Safety and Tolerability of Long-Acting Cabotegravir Plus Recombinant Human Hyaluronidase PH20 in Healthy Adult Participants
A new clinical trial is recruiting patients for Hyaluronidase deficiency
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
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 tests do you recommend to confirm the diagnosis and understand how severe my condition is?,Are there any clinical trials or research studies for MPS IX that I or my child could join?,How often should we have follow-up appointments, and which specialists should be on our care team?,What are the signs that the joint masses need surgical treatment?,Is there any risk that other family members could be affected or be carriers?,What physical activities are safe, and are there any we should avoid to protect the joints?,Are there any patient registries or advocacy groups that could connect us with other families affected by MPS IX?
Common questions about Hyaluronidase deficiency
What is Hyaluronidase deficiency?
Hyaluronidase deficiency, also known as mucopolysaccharidosis type IX (MPS IX), is a very rare inherited condition where the body cannot properly break down a substance called hyaluronan (also called hyaluronic acid). Hyaluronan is a natural sugar-based molecule found throughout the body, especially in joints, skin, and connective tissue. When the enzyme hyaluronidase does not work properly, hyaluronan builds up in tissues and causes damage over time. This condition belongs to a group of diseases called mucopolysaccharidoses (MPS disorders) or lysosomal storage disorders. The most noticeable
How is Hyaluronidase deficiency inherited?
Hyaluronidase deficiency follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Hyaluronidase deficiency typically begin?
Typical onset of Hyaluronidase deficiency is childhood. Age of onset can vary across affected individuals.