Overview
Lethal Larsen-like syndrome is an extremely rare and severe skeletal disorder that affects how bones and joints form before birth. It belongs to a group of conditions called skeletal dysplasias, which means the bones develop abnormally during fetal development. The condition shares some features with Larsen syndrome — such as dislocated joints and unusual facial features — but is far more severe and is typically fatal either before birth or very shortly after birth, which is why it is called 'lethal.' The syndrome is also sometimes referred to as lethal Larsen syndrome or a lethal variant of Larsen syndrome. Babies affected by this condition are usually found to have multiple dislocated joints, abnormal bone development throughout the skeleton, and serious problems with the spine. The face may look different from typical, with a flat midface, wide-set eyes, and a prominent forehead. Because the condition is so severe, the lungs and other vital organs often cannot develop properly, making survival outside the womb extremely unlikely. There is currently no cure or disease-modifying treatment for lethal Larsen-like syndrome. Care is focused on supporting families through diagnosis, genetic counseling, and bereavement. Prenatal imaging and genetic testing play a key role in identifying the condition before birth.
Key symptoms:
Multiple dislocated joints present at birthAbnormal bone formation throughout the skeletonFlat or underdeveloped midfaceWide-set eyesProminent foreheadSevere spinal abnormalitiesShort limbsUnderdeveloped or poorly formed lungsStillbirth or death shortly after birthAbnormal skull shapeCleft palate in some cases
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Neonatal
Begins at or shortly after birth (first 4 weeks)
FDA & Trial Timeline
10 eventsKETAMINE HYDROCHLORIDE: New indication approved
KETALAR: New indication approved
KETAMINE HYDROCHLORIDE: FDA approved
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Lethal Larsen-like syndrome.
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Specialists
View all specialists →No specialists are currently listed for Lethal Larsen-like syndrome.
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 Lethal Larsen-like syndrome.
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
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.What genetic testing should we have done to confirm the diagnosis and find the exact cause?,What is the chance this condition could happen again in a future pregnancy?,Are there prenatal tests available to check for this condition in future pregnancies?,Should other family members be tested for the gene change?,Can you refer us to a bereavement counselor or support group for families who have experienced this?,Are there any research studies or registries we should know about for this condition?,What specialists should be involved in our care going forward?
Common questions about Lethal Larsen-like syndrome
What is Lethal Larsen-like syndrome?
Lethal Larsen-like syndrome is an extremely rare and severe skeletal disorder that affects how bones and joints form before birth. It belongs to a group of conditions called skeletal dysplasias, which means the bones develop abnormally during fetal development. The condition shares some features with Larsen syndrome — such as dislocated joints and unusual facial features — but is far more severe and is typically fatal either before birth or very shortly after birth, which is why it is called 'lethal.' The syndrome is also sometimes referred to as lethal Larsen syndrome or a lethal variant of L
How is Lethal Larsen-like syndrome inherited?
Lethal Larsen-like syndrome follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Lethal Larsen-like syndrome typically begin?
Typical onset of Lethal Larsen-like syndrome is neonatal. Age of onset can vary across affected individuals.