Overview
Oncogenic osteomalacia, also known as tumor-induced osteomalacia (TIO), is a rare condition where a usually small, slow-growing tumor produces too much of a hormone called fibroblast growth factor 23 (FGF23). This hormone tells the kidneys to get rid of phosphorus, a mineral that is essential for strong bones. When FGF23 levels are too high, phosphorus levels in the blood drop very low, causing the bones to become soft and weak — a condition called osteomalacia. The most common symptoms include bone pain, muscle weakness, and fractures that happen with little or no injury. Many patients also experience fatigue and difficulty walking. Because the symptoms develop slowly and can look like other conditions, it often takes years before the correct diagnosis is made. The tumors responsible are usually benign (not cancerous) and can be found almost anywhere in the body, including bones, soft tissues, and the skin. The good news is that oncogenic osteomalacia can often be cured if the tumor is found and completely removed through surgery. When the tumor cannot be located or fully removed, patients are treated with phosphorus supplements and active vitamin D (calcitriol) to manage symptoms. A newer medication called burosumab (Crysvita), which blocks FGF23, has also been approved for use in certain cases of tumor-induced osteomalacia where the tumor cannot be removed or found.
Key symptoms:
Bone pain, especially in the hips, back, and legsMuscle weaknessFractures from minor injuries or stress fracturesDifficulty walking or waddling gaitFatigue and low energyHeight loss over timeJoint painTrouble getting up from a chair or climbing stairsGeneralized body achesBone tenderness when pressedDecreased mobilityMultiple stress fractures in the feet or legs
Clinical phenotype terms (35)— hover any for plain English
Sporadic
Usually appears on its own, not inherited from a parent
Adult
Begins in adulthood (age 18 or older)
FDA & Trial Timeline
4 eventsPeking Union Medical College Hospital — NA
Ultragenyx Pharmaceutical Inc
Crysvita: FDA approved
Crysvita (burosumab-twza) is indicated for the treatment of FGF23-related hypophosphatemia in tumor-induced osteomalacia (TIO) associated with phosphaturic mesenchymal tumors that cannot be curatively resected or localized.
Zometa, Zabel: FDA approved
Treatment of hypercalcemia of malignancy.
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Oncogenic osteomalacia.
2 clinical trialsare actively recruiting — trials can provide access to cutting-edge therapies.
View clinical trials →Rare Disease Specialist
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
Financial Resources
2 resourcesCrysvita
Kyowa Kirin, Inc.
Crysvita — Contact Kyowa Kirin, Inc.
Zometa, Zabel
Novartis Pharmaceuticals Corp.
Travel Grants
No travel grants are currently matched to Oncogenic osteomalacia.
Community
No community posts yet. Be the first to share your experience with Oncogenic osteomalacia.
Start the conversation →Latest news about Oncogenic osteomalacia
Disease timeline:
New recruiting trial: Al18F-NOTA-LM3 PET/CT in Patients With TIO
A new clinical trial is recruiting patients for Oncogenic osteomalacia
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.Has the tumor been located, and if so, can it be surgically removed?,What imaging tests are available to help find the tumor if it hasn't been located yet?,Am I a candidate for burosumab (Crysvita) treatment?,How often will I need blood tests and follow-up imaging?,What are the risks of long-term phosphorus and vitamin D supplementation?,How will we know if the tumor comes back after surgery?,Are there clinical trials or specialized centers I should consider?
Common questions about Oncogenic osteomalacia
What is Oncogenic osteomalacia?
Oncogenic osteomalacia, also known as tumor-induced osteomalacia (TIO), is a rare condition where a usually small, slow-growing tumor produces too much of a hormone called fibroblast growth factor 23 (FGF23). This hormone tells the kidneys to get rid of phosphorus, a mineral that is essential for strong bones. When FGF23 levels are too high, phosphorus levels in the blood drop very low, causing the bones to become soft and weak — a condition called osteomalacia. The most common symptoms include bone pain, muscle weakness, and fractures that happen with little or no injury. Many patients also
How is Oncogenic osteomalacia inherited?
Oncogenic osteomalacia follows a sporadic inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Oncogenic osteomalacia typically begin?
Typical onset of Oncogenic osteomalacia is adult. Age of onset can vary across affected individuals.
Are there clinical trials for Oncogenic osteomalacia?
Yes — 2 recruiting clinical trials are currently listed for Oncogenic osteomalacia on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Oncogenic osteomalacia?
21 specialists and care centers treating Oncogenic osteomalacia are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.
What treatment and support options exist for Oncogenic osteomalacia?
2 patient support programs are currently tracked on UniteRare for Oncogenic osteomalacia. See the treatments and support programs sections for copay assistance, eligibility, and contact details.