Overview
Megalencephaly-capillary malformation-polymicrogyria syndrome, often called MCAP syndrome (also known as macrocephaly-capillary malformation or M-CM syndrome), is a rare condition that affects brain development and blood vessel formation. The name describes its three main features: megalencephaly (an unusually large brain), capillary malformations (pink or red skin birthmarks caused by abnormal small blood vessels), and polymicrogyria (a brain surface that has too many small folds instead of the normal pattern). These changes happen because of a genetic change that causes certain cells to grow and divide too much. People with MCAP syndrome are usually born with a larger-than-normal head, and the head may continue to grow faster than expected. The skin birthmarks are often found on the face, especially around the nose and upper lip, but can appear anywhere on the body. Brain differences can lead to a wide range of challenges including intellectual disability, developmental delays, seizures, and problems with movement and coordination. Some children also have extra fingers or toes, or an asymmetry where one side of the body is larger than the other. There is currently no cure for MCAP syndrome. Treatment focuses on managing symptoms, which may include anti-seizure medications, physical therapy, occupational therapy, speech therapy, and regular brain imaging to watch for fluid buildup. With the right support, many children can make meaningful progress in their development.
Also known as:
Key symptoms:
Unusually large head size (macrocephaly or megalencephaly)Pink or red birthmarks on the skin (capillary malformations), often on the faceIntellectual disability or learning difficultiesDevelopmental delays (sitting, walking, talking later than expected)Seizures or epilepsyAbnormal brain surface with too many small folds (polymicrogyria)Extra fingers or toes (polydactyly)One side of the body larger than the other (body asymmetry or hemihyperplasia)Fluid buildup in the brain (hydrocephalus)Low muscle tone (hypotonia)Problems with coordination and balanceConnective tissue differences such as loose or stretchy skinAbnormal tissue growth between brain hemispheres (megalencephaly with abnormal white matter)
Clinical phenotype terms (35)— hover any for plain English
Sporadic
Usually appears on its own, not inherited from a parent
Neonatal
Begins at or shortly after birth (first 4 weeks)
FDA & Trial Timeline
4 eventsZeus Sleep Ltd — NA
University of Trieste
Belfast Health and Social Care Trust — PHASE3
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Megalencephaly-capillary malformation-polymicrogyria syndrome.
View clinical trials →Clinical Trials
View all trials with filters →No actively recruiting trials found for Megalencephaly-capillary malformation-polymicrogyria syndrome at this time.
New trials open frequently. Follow this disease to get notified.
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 Megalencephaly-capillary malformation-polymicrogyria syndrome.
Community
No community posts yet. Be the first to share your experience with Megalencephaly-capillary malformation-polymicrogyria syndrome.
Start the conversation →Latest news about Megalencephaly-capillary malformation-polymicrogyria syndrome
Disease timeline:
New recruiting trial: Anti-vascular Endothelial Growth Factor (Anti-VEGF) Monotherapy vs Anti-VEGF Followed by Subthreshold Micropulse Laser for Treating Severe Diabetic Macular Oedema When the Central Retina Goes <400 Microns
A new clinical trial is recruiting patients for Megalencephaly-capillary malformation-polymicrogyria syndrome
New recruiting trial: The MICRON Study - A Steno 1 Substudy
A new clinical trial is recruiting patients for Megalencephaly-capillary malformation-polymicrogyria syndrome
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 brain changes did the MRI show, and what do they mean for my child's development?,How often should we repeat brain imaging, and what are we watching for?,What is the best anti-seizure medication for my child, and what are the side effects?,Are there any clinical trials for PIK3CA inhibitors that my child might qualify for?,What therapies do you recommend, and how often should my child receive them?,Should other family members be tested, or is this condition unlikely to affect them?,What signs should prompt me to go to the emergency room immediately?
Common questions about Megalencephaly-capillary malformation-polymicrogyria syndrome
What is Megalencephaly-capillary malformation-polymicrogyria syndrome?
Megalencephaly-capillary malformation-polymicrogyria syndrome, often called MCAP syndrome (also known as macrocephaly-capillary malformation or M-CM syndrome), is a rare condition that affects brain development and blood vessel formation. The name describes its three main features: megalencephaly (an unusually large brain), capillary malformations (pink or red skin birthmarks caused by abnormal small blood vessels), and polymicrogyria (a brain surface that has too many small folds instead of the normal pattern). These changes happen because of a genetic change that causes certain cells to grow
How is Megalencephaly-capillary malformation-polymicrogyria syndrome inherited?
Megalencephaly-capillary malformation-polymicrogyria syndrome follows a sporadic inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Megalencephaly-capillary malformation-polymicrogyria syndrome typically begin?
Typical onset of Megalencephaly-capillary malformation-polymicrogyria syndrome is neonatal. Age of onset can vary across affected individuals.
Which specialists treat Megalencephaly-capillary malformation-polymicrogyria syndrome?
1 specialists and care centers treating Megalencephaly-capillary malformation-polymicrogyria syndrome are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.