Woven Bone Disease (Osteogenesis Imperfecta Type V)
Overview
Woven bone disease is the informal name for Osteogenesis Imperfecta (OI) Type V, a rare genetic disorder that affects the strength and structure of bone. Unlike the classic “brittle‑bone” forms of OI (Types I–IV), Type V is characterized by the presence of “woven” bone on X‑ray, a tendency to develop hyperplastic callus after fractures, and distinctive dental and skin findings.
• **Who it affects:** Both males and females are equally affected. The condition is inherited in an autosomal dominant pattern, meaning a single copy of the mutated gene can cause disease. Approximately 5–10 % of all confirmed OI cases are Type V.1
• **Prevalence:** The overall prevalence of OI is about 1 in 15,000–20,000 live births. With Type V representing roughly 5 % of cases, an estimate is 1 in 300,000‑400,000 births worldwide.2
Because the mutation (most often in the IFITM5 gene) leads to abnormal bone matrix, individuals with Type V experience frequent fractures, short stature, and variable joint laxity. However, unlike some severe OI subtypes, patients usually have normal sclerae (the whites of the eyes) and no hearing loss in early life.
Symptoms
Symptoms can vary widely even within the same family, but the following features are most commonly reported in OI Type V:
- Fractures: Repeated long‑bone fractures (femur, tibia, humerus) often after minor trauma.
- Hyperplastic callus formation: Excessive, tumor‑like bone growth at fracture sites, usually appearing 1‑3 months after injury.
- Woven bone on radiographs: “Cloudy” or “trabecular” appearance that differs from the normal lamellar bone pattern.
- Short stature: Adult height typically 3‑6 inches (7‑15 cm) below average for same‑sex peers.
- Joint contractures or laxity: Stiffness in elbows, knees, and hips; some patients have increased flexibility in shoulders and wrists.
- Dental abnormalities: Dentinogenesis imperfecta is less common than in other OI types, but some patients have tooth discoloration or early‑loss of permanent teeth.
- Skin findings: Small, flat, hyperpigmented skin lesions (sometimes called “café‑au‑lait‑like spots”) have been described.
- Hearing & vision: Generally normal in early childhood; hearing loss may develop later in life (after age 30) similar to other OI forms.
- Muscle weakness & fatigue: Due to reduced mobility and frequent fractures.
- Respiratory issues: In severe cases, thoracic deformities can restrict lung capacity.
Because many of these signs overlap with other OI subtypes, a genetic test is essential for accurate classification.
Causes and Risk Factors
Genetic cause
Type V OI is caused by a specific mutation (c.-14C>T) in the IFITM5 gene, which encodes the protein interferon‑induced transmembrane protein 5. This protein is expressed in osteoblasts (bone‑forming cells) and regulates the mineralization of the extracellular matrix. The mutation leads to an abnormal start codon, producing a protein with an extra five amino acids that disrupts normal bone formation.
Inheritance pattern
- Autosomal dominant: A child has a 50 % chance of inheriting the mutation from an affected parent.
- De‑novo mutation: About 30‑40 % of cases arise spontaneously, with no family history.
Risk factors
- Having a parent (or close relative) with a confirmed IFITM5 mutation.
- In families with known Type V OI, pregnancies conceived without pre‑implantation genetic testing (PGT‑M) have higher recurrence risk.
- Exposure to high‑impact activities in childhood (e.g., contact sports) can increase fracture frequency, though this is a *modifying* rather than causal factor.
Diagnosis
Diagnosing OI Type V requires a combination of clinical assessment, imaging, and molecular testing.
Clinical evaluation
- Detailed family and personal fracture history.
- Physical examination for stature, joint range of motion, skin lesions, and dental health.
Imaging studies
- Plain radiographs: Show characteristic woven (poorly organized) bone, hyperplastic callus, and possible scoliosis.
- Dual‑energy X‑ray absorptiometry (DXA): Measures bone mineral density (BMD); most patients have low BMD, guiding treatment.
- CT or MRI: Used if the hyperplastic callus mimics a tumor or to assess spinal cord compression.
Genetic testing
Next‑generation sequencing (NGS) panels for bone dysplasias, or targeted Sanger sequencing of IFITM5, confirm the diagnosis. Results are definitive when the c.-14C>T mutation is identified.
Laboratory tests (optional)
- Serum calcium, phosphorus, alkaline phosphatase – usually normal, but helpful to rule out metabolic bone disease.
- Vitamin D level – deficiency should be corrected regardless of diagnosis.
Treatment Options
There is no cure for OI Type V, but multidisciplinary care can markedly improve quality of life, reduce fracture risk, and preserve mobility.
Pharmacologic therapy
- Bisphosphonates: Intravenous pamidronate or zoledronic acid are first‑line. They increase BMD and can reduce fracture frequency in children and adults.3 Typical regimen: pamidronate 1‑2 mg/kg IV every 3‑4 months.
- Denosumab: A monoclonal antibody that inhibits RANKL. Limited data suggest benefit in adults who cannot tolerate bisphosphonates.
- Teriparatide (PTH 1‑34): Anabolic agent; used off‑label in selected adults with severe osteoporosis. Must be discontinued after 2 years due to osteosarcoma risk.
- Analgesics/NSAIDs: For acute fracture pain; use cautiously to avoid gastrointestinal side effects.
Surgical and procedural interventions
- Intramedullary rodding: The gold standard for long‑bone stabilization, especially in the femur and tibia. Modern telescopic rods allow growth in children.
- Corrective osteotomies: Address deformities such as bowing or scoliosis.
- Dental management: Regular visits to a dentist familiar with OI; possible placement of crowns or bridges to protect fragile teeth.
- Physical therapy & orthotics: Custom braces or orthotic shoes may reduce fall risk.
Lifestyle and supportive measures
- High‑calcium (1,000–1,300 mg/day) and vitamin D (800–1,000 IU/day) diet or supplements.
- Weight‑bearing activities (e.g., walking, stationary cycling) as tolerated to stimulate bone formation.
- Home safety modifications: padded flooring, handrails, and fall‑prevention aids.
- Regular ophthalmology and audiology screenings, beginning at age 10.
Living with Woven Bone Disease (Osteogenesis Imperfecta Type V)
Managing day‑to‑day life requires a combination of medical follow‑up, physical conditioning, and emotional support.
Practical tips
- Stay active, but smart: Low‑impact activities (swimming, water aerobics) protect joints while strengthening muscles.
- Plan for school or work: Request accommodations such as extra break time, ergonomic chairs, and a flexible schedule for medical appointments.
- Nutrition: Incorporate leafy greens, fortified dairy, nuts, and fatty fish for calcium, vitamin D, and omega‑3s that may reduce inflammation.
- Monitor bone health: Schedule DXA scans every 1–2 years; discuss results with your endocrinologist.
- Psychosocial support: Join OI patient groups (e.g., Little People of America, International Osteogenesis Imperfecta Foundation) for peer mentoring.
- Pregnancy considerations: Women with Type V should receive pre‑conception counseling; bisphosphonates are contraindicated during pregnancy.
Family & caregiver role
Education about safe handling techniques when assisting with transfers can prevent accidental fractures. Caregivers should also keep an updated emergency care plan (including a copy of the genetic test results) readily accessible.
Prevention
Because the genetic mutation cannot be altered after birth, “prevention” focuses on reducing secondary risk factors.
- Genetic counseling: Recommended for carriers planning a pregnancy. Options include carrier testing, prenatal diagnosis (CVS/amniocentesis), or pre‑implantation genetic testing (PGT‑M).
- Fall‑prevention strategies: Clear clutter, use non‑slip mats, install grab bars in bathrooms, ensure adequate lighting.
- Early pharmacotherapy: Starting bisphosphonate therapy in childhood has been shown to improve peak bone mass and lower fracture rates.4
- Vaccinations: Maintain up‑to‑date immunizations (especially influenza and pneumococcal) to avoid respiratory infections that could compromise breathing in the setting of thoracic deformities.
Complications
If not adequately managed, Type V OI can lead to several serious complications:
- Progressive skeletal deformities: Bowing of long bones, scoliosis, and kyphosis may impair mobility.
- Chronic pain: Repeated fractures and surgical hardware can cause persistent nociceptive and neuropathic pain.
- Reduced pulmonary function: Thoracic insufficiency syndrome can lead to restrictive lung disease.
- Hearing loss: Conductive or sensorineural loss may appear in the third or fourth decade.
- Dental collapse: Teeth may fracture or become infected, leading to poor nutrition.
- Psychosocial impact: Anxiety, depression, and social isolation are common without supportive counseling.
- Rare malignant transformation: Hyperplastic callus rarely mimics a sarcoma; careful radiologic follow‑up is essential.
When to Seek Emergency Care
- Severe, worsening pain after a fall or minor bump, especially if the limb looks deformed or is an abnormal length.
- Sudden loss of sensation or movement in an arm or leg (possible nerve or vascular injury).
- Difficulty breathing, chest pain, or a feeling of tightness in the chest – signs of a possible rib fracture or pulmonary compromise.
- Unexplained swelling or a rapidly growing, painful mass at a previous fracture site (could indicate a complicated hyperplastic callus or infection).
- Fever (>100.4 °F or 38 °C) with localized warmth, redness, or drainage from a fracture site – indicating possible osteomyelitis.
- Sudden vision changes or hearing loss accompanied by head trauma.
Prompt evaluation can prevent permanent disability and ensure timely treatment.
**References**
- Forlino A, Marini JC. Osteogenesis imperfecta. Lancet. 2016;387(10028):1657‑1671. DOI:10.1016/S0140-6736(15)00143-0.
- Goriely A, et al. Epidemiology of osteogenesis imperfecta. Orthobullets. 2021.
- Mayo Clinic. Osteogenesis imperfecta - Treatment. https://www.mayoclinic.org. Accessed May 2026.
- Centers for Disease Control and Prevention. Bone Health and Osteoporosis. https://www.cdc.gov. Updated 2023.