Boston London Toronto
Rare Disease Consortium

Collaborating Across Borders to

Advance Pediatric Neurovascular Care.

An alliance of top clinicians in Boston, London, and Toronto working together to treat the most complex diagnoses.

A Tri-City Collaboration

At BLT, we believe that no child should face a complex diagnosis alone. That’s why clinicians across Boston, London, and Toronto have joined forces to accelerate diagnosis, share expertise, and publish the most up-to-date research in pediatric neurovascular care.

Learn More About BLT

Boston, London, and Toronto medical teams working together on rare neurovascular conditions

Cerebrovascular Surgery and Interventions Center

BOSTON TEAM

Great Ormond Street Hospital Department of Neurosurgery

LONDON TEAM

SickKids Paediatric Neurovascular Program

TORONTO TEAM

Diseases We Treat

Our teams are currently focused on diagnosing and treating a range of rare and complex neurovascular diseases.

Cerebral Proliferative Angiopathy

Cerebral Proliferative Angiopathy is an uncommon vascular condition of the brain characterized by a diffuse network of abnormal blood vessels interwoven with healthy brain tissue.

Unlike a typical arteriovenous malformation (AVM), CPA develops slowly over time and often involves a broad area of the brain, making treatment more complex. Symptoms may include seizures, headaches, or progressive neurological deficits.

Moyamoya Disease

Moyamoya disease is a rare, progressive cerebrovascular disorder caused by the narrowing or blockage of arteries at the base of the brain, particularly around the internal carotid arteries. As blood flow becomes restricted, the brain compensates by forming a network of tiny, fragile vessels.

This condition can lead to strokes, transient ischemic attacks (TIAs), seizures, and cognitive decline. It most commonly affects children, but can also present in adults.

Brain imaging showing Vein of Galen malformation, a rare condition where blood vessels connect abnormally.

Vein of Galen Malformation (VOGM)

Vein of Galen Malformation is a rare congenital vascular anomaly in which abnormal connections between arteries and the deep midline vein of the brain (the vein of Galen) form before birth.

This high-flow shunt can place significant strain on an infant’s heart and brain, sometimes causing heart failure or hydrocephalus shortly after birth. Advances in endovascular treatment have greatly improved outcomes, allowing many affected infants to receive life-saving intervention in the first months of life.

Cavernous Malformations

Cavernous malformations are clusters of abnormally formed, thin-walled blood vessels that resemble small mulberries within the brain or spinal cord. These lesions can leak or bleed, sometimes leading to headaches, seizures, or neurological changes.

While some are discovered incidentally and never cause symptoms, others require close monitoring or surgical treatment depending on their size, location, and bleeding risk.

Arteriovenous Malformations (AVMs)

Arteriovenous malformations (AVMs) are tangles of abnormal blood vessels in which arteries connect directly to veins without the normal capillary bed.

This high-pressure connection can strain or rupture vessels, leading to seizures, headaches, or life-threatening brain hemorrhage.

AVMs may remain silent for years or present suddenly, and treatment is carefully tailored to the patient, often involving surgery, radiosurgery, or embolization.

Arteriovenous Fistulas (AVFs)

Arteriovenous fistulas (AVFs) are abnormal, direct links between arteries and veins that bypass the body’s normal blood vessel network.

In the brain or spinal cord, these high-flow connections can cause pressure changes that result in headaches, seizures, or bleeding.

Some AVFs develop after trauma or surgery, while others are congenital, and they are often treated with minimally invasive endovascular techniques or surgery.

Stroke in Children

Stroke in children, though less common than in adults, can occur when blood flow to part of the brain is blocked (ischemic stroke) or when a blood vessel ruptures and causes bleeding (hemorrhagic stroke).

Causes often include congenital heart disease, blood disorders, or vascular conditions such as AVMs or moyamoya disease.

Symptoms may be subtle—like weakness, speech difficulty, or sudden behavioral change—making fast recognition and urgent treatment critical for recovery.

MORE ABOUT OUR WORK

HOW IT WORKS :
COLLABORATION

Whether through monthly case rounds, real-time consultations, or multi-center studies, our collaboration model ensures every child benefits from world-class expertise, no matter where they are.

BLT Network Collaboration Showing Sick Patient

Complex/Rare Case Identified

Consensus Recommendation

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Monthly Joint Review

BLT Network collaboration showing consultation

Implement Patient Care

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Learn More About Collaboration

Upcoming Events & Meeting Summaries

Join SickKids experts on October 25, 2025, for Neurovascular Family Education Day. Learn about AVMs, Vein of Galen Malformations, and Cavernous Malformations while connecting with families and caregivers.

Upcoming Event : Neurovascular Family Education Day 2025

Join SickKids experts on October 25, 2025, for Neurovascular Family Education Day. Learn about AVMs, Vein of Galen Malformations, and Cavernous Malformations while connecting with families and caregivers.

Sep 17

BLT Meeting London 2025 announcement – international pediatric neurovascular collaboration

Announcement: Boston–London–Toronto (BLT) Meeting – London 2025

Join the Boston–London–Toronto Meeting in London on November 14, 2025, at Great Ormond Street Hospital. A day of pediatric neurovascular research, collaboration, and networking.

Aug 27

Moyamoya Family Education Day 2025: Growing New Branches

Highlights from Moyamoya Family Education Day 2025, featuring expert talks on surgery, genetics, research, and family support, alongside inspiring patient perspectives.URL Slug: /blt-day-meeting-june-2023

May 10

Contact Us

Boston London Toronto Rare Disease Consortium

Connecting experts across Boston, London, and Toronto to fast-track innovation in precision medicine.

Visit Us

BLT is a cross-continental alliance focused on rare disease diagnosis treatment and awareness.

Boston London Toronto
Rare Disease Consortium

A Tri-City Collaboration

Diseases We Treat

Cerebral Proliferative Angiopathy

Moyamoya Disease

Vein of Galen Malformation (VOGM)

Cavernous Malformations

Arteriovenous Malformations (AVMs)

Arteriovenous Fistulas (AVFs)

Stroke in Children

HOW IT WORKS :
COLLABORATION

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Upcoming Events & Meeting Summaries

Upcoming Event : Neurovascular Family Education Day 2025

Announcement: Boston–London–Toronto (BLT) Meeting – London 2025

Moyamoya Family Education Day 2025: Growing New Branches

Contact Us

Boston

London

Toronto

ABOUT

UPDATES

MEMBERS

IMPACT

Boston

London

Toronto

Boston London Toronto Rare Disease Consortium

A Tri-City Collaboration

Diseases We Treat

Cerebral Proliferative Angiopathy

HOW IT WORKS : COLLABORATION

1

3

2

4

Upcoming Events & Meeting Summaries

Upcoming Event : Neurovascular Family Education Day 2025

Announcement: Boston–London–Toronto (BLT) Meeting – London 2025

Moyamoya Family Education Day 2025: Growing New Branches

Contact Us

Boston

London

Toronto

ABOUT

UPDATES

MEMBERS

IMPACT

Boston

London

Toronto

Boston London Toronto
Rare Disease Consortium

HOW IT WORKS :
COLLABORATION