Overview
Familial lambdoid synostosis is a rare condition in which one or both of the lambdoid sutures in the skull close too early (a process called craniosynostosis). The lambdoid sutures are located at the back of the skull, where the parietal bones meet the occipital bone. In a growing baby, these sutures normally remain open to allow the brain and skull to grow properly. When they fuse prematurely, the skull cannot expand normally in that area, which can lead to an abnormal head shape — often a flattening on one side of the back of the head (called plagiocephaly) or flattening across the entire back of the head (called brachycephaly). In the familial form, this condition runs in families, meaning it is inherited rather than occurring by chance. This condition is now classified as 'OBSOLETE' in the Orphanet database, meaning it has likely been reclassified or merged into a broader category of craniosynostosis conditions. Babies with lambdoid synostosis may have a visibly abnormal head shape noticed at birth or in the first few months of life. In some cases, increased pressure inside the skull (intracranial pressure) can develop if the brain does not have enough room to grow. Treatment typically involves surgery to open the fused suture and reshape the skull, ideally performed in infancy when the skull bones are still soft and the brain is growing rapidly. Outcomes after surgery are generally good, especially when the condition is identified and treated early. Because this is a familial form, genetic counseling is recommended for affected families.
Key symptoms:
Abnormal head shape, especially flattening at the back of the skullAsymmetry of the skull (one side of the back of the head may look different from the other)A visible or palpable bony ridge along the lambdoid suture at the back of the headBulging or fullness on the opposite side of the skull from the fused sutureEar position that appears uneven (one ear may be pushed back or lower)Possible increased pressure inside the skull (headaches, irritability, vomiting in infants)Slow growth of the head circumferencePossible developmental delays if intracranial pressure is not treated
Autosomal dominant
Passed on from just one parent; each child has about a 50% chance of inheriting it
Neonatal
Begins at or shortly after birth (first 4 weeks)
Treatments
No FDA-approved treatments are currently listed for OBSOLETE: Familial lambdoid synostosis.
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Specialists
View all specialists →No specialists are currently listed for OBSOLETE: Familial lambdoid synostosis.
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 OBSOLETE: Familial lambdoid synostosis.
Community
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Caregiver Resources
NORD Caregiver Resources
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Mental Health Support
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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.How severe is my child's lambdoid synostosis, and is surgery recommended?,What type of surgery do you recommend, and what are the risks and benefits?,At what age should the surgery ideally be performed?,Will my child need helmet therapy after surgery, and for how long?,Should other family members or future children be screened for this condition?,What signs of complications should I watch for after surgery?,What is the long-term outlook for my child's development and head shape?
Common questions about OBSOLETE: Familial lambdoid synostosis
What is OBSOLETE: Familial lambdoid synostosis?
Familial lambdoid synostosis is a rare condition in which one or both of the lambdoid sutures in the skull close too early (a process called craniosynostosis). The lambdoid sutures are located at the back of the skull, where the parietal bones meet the occipital bone. In a growing baby, these sutures normally remain open to allow the brain and skull to grow properly. When they fuse prematurely, the skull cannot expand normally in that area, which can lead to an abnormal head shape — often a flattening on one side of the back of the head (called plagiocephaly) or flattening across the entire ba
How is OBSOLETE: Familial lambdoid synostosis inherited?
OBSOLETE: Familial lambdoid synostosis follows a autosomal dominant inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does OBSOLETE: Familial lambdoid synostosis typically begin?
Typical onset of OBSOLETE: Familial lambdoid synostosis is neonatal. Age of onset can vary across affected individuals.