Wyburn-Mason syndrome, also called Bonnet–Dechaume–Blanc syndrome, is a very rare condition present at birth in which blood vessels form direct connections between arteries and veins—called arteriovenous malformations (AVMs)—without the normal tiny capillaries between them. These AVMs most often appear in the retina (the light-sensing layer at the back of the eye) and in the brain, but they can also affect the face or other parts of the body. Symptoms usually show up in late childhood or early adulthood when vision changes, headaches, or neurological signs prompt medical evaluation Wikipedia.
Wyburn-Mason syndrome (pronounced “WHY-burn MAY-sun”) is a very rare birth condition in which some of the body’s blood vessels grow in an unusual, tangled way called an arteriovenous malformation (AVM).
Arteries normally carry blood away from the heart under high pressure.
Veins normally carry blood back to the heart under low pressure.
In an AVM, the two kinds of vessels meet directly, without the normal tiny “exchange pipes” (capillaries) in between.
Because the high-pressure artery blood flows straight into the low-pressure vein, the vessel wall stretches, twists, and forms a cluster of loops that looks a bit like a bowl of spaghetti.
In Wyburn-Mason syndrome, those clusters usually form in two main places:
Behind the eye, along the retina and optic nerve.
Inside the brain, most often in the mid-brain region (thalamus, basal ganglia, or cerebral cortex).
The syndrome is sometimes called Bonnet–Dechaume–Blanc syndrome after French doctors who first described it in 1937–1938, but “Wyburn-Mason” is the name used most often today.
Types of Wyburn-Mason Syndrome
Because every person’s tangle of vessels is different, doctors group the condition into three broad types. These categories simply help doctors plan tests and treatments; they do not change the basic problem of the blood-vessel tangle.
| Type | Plain-English Description |
|---|---|
| Type 1 (Complete or “Classic”) | AVM is found in the retina and in the brain. Both areas may cause symptoms. |
| Type 2 (Ocular-Dominant) | AVM is mainly around the eye (retina, optic nerve, eyelids), with little or no brain involvement visible on scans. |
| Type 3 (Cerebral-Dominant) | AVM is mainly inside the brain. The eye may look normal or show only tiny vessel twists. |
Causes / Risk Factors
Wyburn-Mason syndrome is believed to begin very early in fetal life, before birth. No single “trigger” is proven, but researchers list many possible influences.
Below are 20 plain-English explanations of factors that may turn normal vessel growth into an AVM. (Remember, these are theories; no one factor alone “guarantees” the syndrome.)
Random Gene Copy Error
Sometimes, while a baby is forming, a gene that tells vessels how to branch makes a one-off spelling mistake.
Somatic Mutation in the RASA1 Pathway
“Somatic” means not inherited. A change in a gene that controls Ras-Map signaling can let arteries link to veins too soon.
Low Oxygen Pocket in the Early Brain
If a tiny area gets less oxygen for a few hours, vessels may sprout wildly to “catch up,” then fuse abnormally.
Imbalanced VEGF (Vascular Endothelial Growth Factor)
Too much VEGF acts like extra fertilizer, pushing vessels to grow too fast.
Notch Signaling Pathway Error
Notch proteins are “traffic police” for new blood-vessel sprouts. A glitch removes the stop signal, leading to a tangle.
Abnormal Tie2-Angiopoietin Loop
Tie2 is a receptor that keeps young vessels stable. If its partner, angiopoietin-2, rises suddenly, walls stay flimsy and fuse.
Maternal Rubella or CMV Infection
Some viruses in early pregnancy disrupt vessel patterning genes, though proof is limited.
Exposure to High Blood Sugar in Utero
Diabetic mothers may have glucose levels that nudge fetal vessel growth abnormally.
Environmental Toxin (e.g., Smoking, Solvents)
Chemicals can block normal DNA methylation marks, confusing growth signals.
Chromosomal Mosaicism
Only some cells carry an extra or missing chromosome piece; the patchy error yields patchy AVMs.
Abnormal Neural Crest Cell Migration
Early nerve-support cells also guide vessel tracks; if they wander, vessels follow the wrong map.
Twist-1 (TWIST1) Transcription Factor Variant
Rare variants may loosen vessel wall structure.
Endothelial-Pericyte Miscommunication
Pericytes wrap vessels like tape; a signaling miss means arteries connect to veins before tape arrives.
Familial AVM History (Polygenic)
A parent with any AVM raises background risk, hinting at multiple low-effect genes.
Epigenetic Silencing of ENG (Endoglin)
Endoglin is key in hereditary hemorrhagic telangiectasia; if silenced in a brain patch, localized AVM may form.
Abnormal Hemodynamic Shear Stress in Fetus
If blood pressure pulses are uneven, vessels may shortcut across high-pressure zones.
Placental Growth Factor Overflow
Excess PlGF leaks into fetal blood and misdirects vessel branching.
Maternal Hypoxia (e.g., high altitude)
Long-term low oxygen can up-regulate angiogenic genes.
Wnt/β-catenin Pathway Dysregulation
This pathway seals vessel junctions; poor sealing may cause direct artery-to-vein fusions.
Unknown Multi-Hit Combination
Most likely, two or three small hits (gene + environment + timing) combine to create the syndrome.
Common Symptoms
Every person is unique, but the 15 signs below appear again and again in medical reports. Each paragraph explains what the symptom feels like and why it happens, using simple English.
Blurred or Distorted Vision in One Eye
The vessel tangle on the retina bends light unevenly, so images smear or look wavy.
Sudden Vision Loss (Painless)
A fragile AVM vein may leak or bleed, blocking the retina like paint on a camera lens.
“Floating” Dark Spots (Floaters)
Tiny clots or blood cells drift in the gel inside the eye, casting moving shadows.
Eye Redness and Pulsing
Artery-level pressure makes surface veins swell and throb visibly with each heartbeat.
Headache (Often One-Sided)
The brain AVM steals blood from normal tissue, causing local pressure and ache.
Seizures
Electrical storms start near the AVM if nearby neurons get irritated by low oxygen or tiny bleeds.
Weakness on One Side of the Body
If the AVM presses on motor pathways, signals from the brain to muscles weaken.
Face Tingling or Numbness
Sensory pathways in the thalamus or brainstem can be squashed by the swollen AVM.
Difficulty Speaking (Slurred or Halting Words)
When language areas are near the tangle, swelling slows word-forming circuits.
Double Vision or Eye Drifting
Pressure on the optic nerve or eye muscles upsets the eyes’ “aim,” so two images appear.
Noisy Whooshing Sound in the Ear (Bruit)
High-speed blood flow makes a rushing sound person hears inside the skull.
Unequal Pupil Size (Anisocoria)
If nerve fibers that control pupil shape are pinched on one side, one pupil stays bigger.
Facial Asymmetry or Swelling
Surface AVM vessels may enlarge one cheek or eyelid more than the other.
Nosebleeds (Rare but Reported)
Fragile nose vessels can mirror eye vessels; minor trauma triggers bleeding.
Learning or Behavior Problems in Children
Long-term low oxygen in certain brain areas may slow school performance or cause mood shifts.
Diagnostic Tests
Doctors pick from a “toolbox” of 20 tests to confirm Wyburn-Mason syndrome, map its extent, and plan care. The tests are grouped into five categories for clarity.
A. Physical‐Exam Tests (Bedside or Clinic Room)
Cranio-facial Inspection
Doctor looks for swollen eyelids, bulging veins, or face asymmetry that hint at a surface AVM.
Direct Ophthalmoscopy
A hand-held light lets the doctor “peek” through the pupil at the retina to spot red-blue vessel loops.
Neurological Quick Check
Simple commands (“squeeze my hands, smile, follow my finger”) reveal weakness or vision gaps.
Blood Pressure and Heart Rate Screening
High systemic pressure can worsen AVM leaks; trending BP helps risk planning.
B. Manual (Hands-On or Low-Tech) Vision Tests
Snellen Visual-Acuity Chart
The familiar letter chart measures sharpness; sudden drop may signal retinal bleed.
Color-Vision Plates (Ishihara)
Damaged optic nerve fibers often lose red-green detection first.
Amsler Grid
A checkered card; wavy or missing lines show macular distortion from vessel swelling.
Manual Goldmann Perimetry
A moving light dot charts the patient’s side vision on paper, mapping blind spots.
C. Laboratory & Pathological Tests
Complete Blood Count (CBC)
Looks for anemia from slow retinal bleeding and checks platelets before any surgery.
Erythrocyte Sedimentation Rate (ESR) & C-Reactive Protein (CRP)
Though usually normal, raised numbers hint at secondary inflammation after a bleed.
Coagulation Profile (PT/INR, aPTT)
Ensures blood-clotting ability is stable; vital before embolization or surgery.
Serum Vascular-Growth-Factor Panel
Research labs measure VEGF/PlGF levels to study disease activity.
Targeted Gene Panel for AVM Syndromes
A blood sample checks for RASA1, ENG, or ACVRL1 variants that sometimes overlap.
D. Electrodiagnostic Tests
Electroretinography (ERG)
Sticky eye electrodes record the retina’s electric “flash” response; AVM areas may show weakened waves.
Visual-Evoked Potentials (VEP)
A flashing screen and scalp wires chart the speed of optic-nerve signals; slow peaks suggest nerve compression.
Electroencephalogram (EEG)
20–30 scalp sensors detect seizure spikes born near the brain AVM.
Brainstem Auditory-Evoked Response (BAER)
Click sounds test nerve pathways near mid-brain AVMs that could affect hearing and balance.
E. Imaging Tests
Wide-Field Fundus Photography & Fluorescein Angiography
A special camera takes color and dye-contrast pictures, lighting up abnormal loops and leaks on the retina.
Magnetic-Resonance Imaging (MRI) with Contrast
Provides a 3-D map of brain AVM size, nearby nerves, and any tiny bleeds; no radiation is involved.
Digital-Subtraction Angiography (DSA) or CT-Angiography (CTA)
Contrast dye is injected into an arm or groin artery; rapid X-ray frames trace blood flow, showing exactly which arteries feed and which veins drain the tangle — the “gold standard” before treatment.
Non-Pharmacological Treatments
Observation & Monitoring
Description: Regular imaging (MRI or angiogram) and eye exams.
Purpose: To detect changes early before serious complications.
Mechanism: Tracks AVM size and blood flow over time NCBI.
Endovascular Embolization
Description: A catheter delivers particles or glue into the AVM to block flow.
Purpose: To lower bleeding risk and shrink the AVM.
Mechanism: Occludes abnormal channels PubMed.
Surgical Resection
Description: Direct removal of the AVM through open surgery.
Purpose: To cure or greatly reduce risk in high-risk lesions.
Mechanism: Excises malformed vessels PubMed.
Stereotactic Radiosurgery
Description: Focused, high-dose radiation aimed at the AVM.
Purpose: To close the AVM gradually without open surgery.
Mechanism: Thickens and seals vessel walls PubMed.
Laser Photocoagulation
Description: Uses laser to seal leaking retinal vessels.
Purpose: To prevent hemorrhage in the eye.
Mechanism: Burns and closes small vessels.
Photodynamic Therapy (PDT)
Description: Injected light-activated drug is triggered by laser.
Purpose: To block retinal AVMs with minimal heat damage.
Mechanism: Clot formation in target vessels Wikipedia.
Visual Rehabilitation
Description: Training exercises to improve remaining vision.
Purpose: To help patients adapt if sight is reduced.
Mechanism: Strengthens alternative visual pathways.
Occupational Therapy
Description: Retrains daily living skills after neurological injury.
Purpose: To regain independence in tasks like dressing or cooking.
Mechanism: Repetitive practice rewires brain-muscle connections.
Physical Therapy
Description: Strength and balance exercises.
Purpose: To address weakness or coordination issues.
Mechanism: Builds muscle and improves neural control.
Low-Vision Aids
Description: Magnifiers, electronic readers, specialized glasses.
Purpose: To maximize use of remaining vision.
Mechanism: Enlarges images and enhances contrast.
Adaptive Devices
Description: Talking clocks, tactile markers.
Purpose: To support daily tasks despite vision loss.
Mechanism: Provides sensory alternatives.
Hearing Therapy
Description: Devices or training for hearing loss from facial AVMs.
Purpose: To maintain communication.
Mechanism: Amplification and auditory retraining.
Speech Therapy
Description: Exercises to improve articulation and voice.
Purpose: To correct speech problems from neural involvement.
Mechanism: Strengthens vocal muscles and breathing patterns.
Psychological Counseling
Description: Emotional support and coping strategies.
Purpose: To manage anxiety, depression, or stress.
Mechanism: Cognitive techniques build resilience.
Social Work Support
Description: Guidance on healthcare access, insurance, and aid.
Purpose: To connect patients with needed resources.
Mechanism: Case management smooths care coordination.
Support Groups
Description: Peer meetings for sharing experiences.
Purpose: To reduce isolation and learn coping tips.
Mechanism: Peer support boosts morale.
Protective Eyewear
Description: Safety glasses during sports or work.
Purpose: To prevent eye injury that could trigger bleeding.
Mechanism: Shields fragile vessels.
Lifestyle Modifications
Description: Avoid heavy lifting or straining.
Purpose: To keep blood pressure spikes from stressing AVMs.
Mechanism: Less pressure on malformed vessels.
Head Elevation
Description: Sleeping with head elevated.
Purpose: To reduce intracranial pressure and headache.
Mechanism: Gravity helps drain fluid.
Nutritional Counseling
Description: Diet guidance for vascular health.
Purpose: To strengthen vessel walls and reduce inflammation.
Mechanism: Supplies building blocks for healthy blood vessels.
Drug Treatments
Dexamethasone (Corticosteroid)
Dosage: 4–10 mg daily
Purpose: To reduce brain swelling and headache.
Mechanism: Suppresses inflammation and fluid buildup NCBI.
Acetazolamide (Carbonic anhydrase inhibitor)
Dosage: 250–500 mg twice daily
Purpose: To lower elevated intracranial pressure.
Mechanism: Decreases cerebrospinal fluid production NCBI.
Bevacizumab (Anti-VEGF antibody, intravitreal)
Dosage: 1.25 mg injection monthly
Purpose: To reduce retinal swelling and bleeding.
Mechanism: Blocks vessel growth signals ScienceDirect.
Carbamazepine (Anticonvulsant)
Dosage: 200–400 mg twice daily
Purpose: To control seizures from brain AVMs.
Mechanism: Stabilizes sodium channels in neurons.
Valproic Acid (Anticonvulsant)
Dosage: 500–1,000 mg daily
Purpose: Seizure prevention.
Mechanism: Boosts GABA activity in the brain.
Sirolimus (mTOR inhibitor)
Dosage: 0.8–2 mg daily
Purpose: Experimental use to slow AVM growth.
Mechanism: Inhibits cell pathways that promote vessel formation ScienceDirect.
Interferon α (Immunomodulator)
Dosage: 3 million IU three times weekly
Purpose: Off-label to inhibit abnormal vessel growth.
Mechanism: Modulates immune response and angiogenesis.
Propranolol (Beta-blocker)
Dosage: 1–2 mg/kg daily
Purpose: Experimental therapy to reduce blood flow through AVM.
Mechanism: Lowers heart rate and vessel pressure.
Tacrolimus (Calcineurin inhibitor)
Dosage: 0.1 mg/kg daily
Purpose: Investigational immunosuppression for vessel stability.
Mechanism: Inhibits T-cell activation, reducing inflammation.
Pentoxifylline (Hemorheologic agent)
Dosage: 400 mg three times daily
Purpose: To improve blood flow properties.
Mechanism: Increases red cell flexibility and lowers viscosity.
Dietary Molecular & Herbal Supplements
(Note: Limited direct evidence for Wyburn-Mason syndrome; these support overall vascular health.)
Curcumin (Turmeric)
Dosage: 500–1,000 mg of 95% curcumin daily
Function: Anti-inflammatory and antioxidant.
Mechanism: Inhibits NF-κB and COX-2 pathways PMCThe Open Medicine Journal.
Omega-3 Fatty Acids
Dosage: 1–2 g EPA+DHA daily
Function: Anti-inflammatory and vessel health.
Mechanism: Produces anti-inflammatory mediators.
Green Tea Extract (EGCG)
Dosage: 300–400 mg daily
Function: Antioxidant, mild VEGF inhibition.
Mechanism: Blocks signals for new vessel growth.
Quercetin
Dosage: 500 mg twice daily
Function: Vessel stabilization and anti-inflammation.
Mechanism: Inhibits histamine release, supports capillaries.
Vitamin D₃
Dosage: 1,000–2,000 IU daily
Function: Immune regulation and vessel function.
Mechanism: Modulates endothelial cells.
Vitamin C
Dosage: 500–1,000 mg daily
Function: Collagen synthesis for vessel walls.
Mechanism: Cofactor for structural enzymes.
Vitamin E
Dosage: 200 IU daily
Function: Antioxidant protection of vessels.
Mechanism: Scavenges free radicals.
Ginkgo Biloba
Dosage: 120–240 mg daily
Function: Improves microcirculation.
Mechanism: Enhances nitric oxide, reduces viscosity.
Garlic Extract
Dosage: 300–600 mg aged extract daily
Function: Vasodilation and antioxidant.
Mechanism: Releases nitric oxide, reduces clotting.
Resveratrol
Dosage: 150–500 mg daily
Function: Anti-inflammatory, vessel support.
Mechanism: Activates SIRT1 pathway.
Boswellia Serrata
Dosage: 300–400 mg thrice daily
Function: Anti-inflammatory.
Mechanism: Inhibits 5-lipoxygenase.
Magnesium
Dosage: 200–400 mg daily
Function: Regulates vascular tone.
Mechanism: Acts as calcium antagonist in vessels.
Coenzyme Q10
Dosage: 100–200 mg daily
Function: Mitochondrial support and antioxidant.
Mechanism: Reduces oxidative stress in endothelium.
Alpha-Lipoic Acid
Dosage: 300–600 mg daily
Function: Antioxidant regeneration.
Mechanism: Regenerates other antioxidants, protects vessels.
L-Arginine
Dosage: 2–3 g daily
Function: Precursor for nitric oxide.
Mechanism: Relaxes vessel walls, improves flow.
Regenerative & Stem Cell Drugs
Filgrastim (G-CSF)
Dosage: 5 µg/kg daily for 5 days
Function: Boosts white blood cell production.
Mechanism: Stimulates neutrophil precursors.
Erythropoietin (EPO)
Dosage: 50–150 IU/kg thrice weekly
Function: Increases red cell count.
Mechanism: Stimulates erythroid progenitors.
Plerixafor
Dosage: 0.24 mg/kg SC daily
Function: Mobilizes stem cells.
Mechanism: Blocks CXCR4, releasing cells into blood.
Tacrolimus
Dosage: 0.05 mg/kg daily
Function: Immune modulation for tissue repair.
Mechanism: Inhibits calcineurin, lowers inflammation.
Interleukin-2 (IL-2)
Dosage: 1–2 million IU daily
Function: Encourages lymphocyte growth.
Mechanism: Activates T-cell proliferation.
Mesenchymal Stem Cell Therapy
Dosage: 1–2 million cells/kg infusion
Function: Potential vessel stabilization.
Mechanism: Paracrine factors promote repair.
Surgical Procedures
Endovascular Embolization
Why: To block AVM blood flow and prevent hemorrhage.
How: Catheter-delivered embolic agents seal off abnormal vessels PubMed.
Microsurgical Resection
Why: To remove high-risk AVMs that cannot be embolized.
How: Direct surgical excision under microscope guidance PubMed.
Stereotactic Radiosurgery
Why: To close AVMs in deep or hard-to-reach areas.
How: Focused beams of radiation induce vessel closure over months PubMed.
Vitrectomy with Laser
Why: To treat bleeding in the eye.
How: Removes vitreous gel and uses laser to seal retinal vessels.
Ocular Artery Ligation
Why: When embolization isn’t possible, cuts blood flow to the AVM.
How: Surgically ties off the artery supplying the retina Wikipedia.
Prevention Strategies
Regular eye exams
Good blood pressure control
Avoid smoking
Limit heavy lifting/straining
Wear protective eyewear
Manage stress
Eat an antioxidant-rich diet
Limit alcohol
Stay well-hydrated
Promptly report new headaches or vision changes
When to See a Doctor
Sudden vision loss or blurring
Severe or persistent headaches
New seizures
Weakness or numbness on one side
Speech difficulties
Sudden facial swelling or skin changes
Dark spots or floaters in vision
Balance problems
What to Eat & What to Avoid
Eat:
Leafy greens
Berries
Fatty fish
Nuts & seeds
Whole grains
Avoid:
6. High-sodium foods
7. Processed meats
8. Sugary drinks
9. Excess caffeine
10. Trans fats
Frequently Asked Questions
What causes Wyburn-Mason syndrome?
A developmental error in fetal blood vessel formation causes AVMs Wikipedia.Is it hereditary?
No—it occurs sporadically, not passed down in families Wikipedia.How common is it?
Extremely rare—fewer than 60 cases reported by 2025.What symptoms occur?
Vision changes, headaches, seizures, or neurological deficits from bleeding or pressure.How is it diagnosed?
Eye exams with fluorescein angiography, MRI/CT of the brain, and angiograms.Can it be cured?
There is no single cure, but embolization, surgery, and radiosurgery can control AVMs PubMed.What is the outlook?
Many AVMs remain stable. Interventions are reserved for high-risk lesions.Can other organs be affected?
Rarely, AVMs appear in skin, bone, or internal organs.What is bleeding risk?
About 2–4% annual risk of brain AVM rupture PubMed.Will it shorten life?
Untreated severe AVMs can be life-threatening, but proper care often yields normal lifespans.Is radiosurgery safe?
Yes, it is a noninvasive, well-tolerated way to close AVMs over time PubMed.Can children have it?
Yes, though symptoms often don’t appear until later childhood or adulthood.Are there support groups?
Very few specifically for Wyburn-Mason, but general AVM groups can help.What about pregnancy?
Pregnancy doesn’t cause new AVMs, but increased blood volume may worsen existing ones. Careful monitoring is needed.How often should I follow up?
At least annually, or more often if symptoms change or after treatment.
Disclaimer: Each person’s journey is unique, treatment plan, life style, food habit, hormonal condition, immune system, chronic disease condition, geological location, weather and previous medical history is also unique. So always seek the best advice from a qualified medical professional or health care provider before trying any treatments to ensure to find out the best plan for you. This guide is for general information and educational purposes only. Regular check-ups and awareness can help to manage and prevent complications associated with these diseases conditions. If you or someone are suffering from this disease condition bookmark this website or share with someone who might find it useful! Boost your knowledge and stay ahead in your health journey. We always try to ensure that the content is regularly updated to reflect the latest medical research and treatment options. Thank you for giving your valuable time to read the article.
The article is written by Team RxHarun and reviewed by the Rx Editorial Board Members
Last Updated: August 07, 2025.
Racemose Hemangioma
