Overview
Lethal left ventricular non-compaction-seizures-hypotonia-cataract-developmental delay syndrome is an extremely rare and severe genetic condition that affects multiple body systems, most critically the heart and brain. The disease is sometimes referred to by its Orphanet code ORPHA:478049. In this condition, the left side of the heart does not develop properly — the heart muscle stays in a spongy, unfinished state instead of becoming firm and compact as it normally should. This is called 'left ventricular non-compaction' (LVNC), and it makes it very hard for the heart to pump blood effectively. Beyond the heart, children with this syndrome typically experience seizures, very low muscle tone (called hypotonia), clouding of the eye lens (cataracts), and significant delays in development and learning. The combination of these problems makes this condition extremely serious. Most reported cases have been fatal in infancy or early childhood, which is reflected in the word 'lethal' in the disease name. There is currently no cure for this syndrome. Treatment focuses on managing each symptom as best as possible — for example, medications to support heart function, anti-seizure drugs, and early intervention therapies for developmental delays. Because this disease is so rare, most of what is known comes from a very small number of reported cases, and research is still in very early stages.
Key symptoms:
Abnormal heart muscle structure (left ventricular non-compaction) making the heart weakSeizures (episodes of uncontrolled electrical activity in the brain)Very low muscle tone (hypotonia) — baby feels floppyCataracts — clouding of the lens in one or both eyesSignificant delays in reaching developmental milestones like sitting, walking, and talkingIntellectual disabilityHeart failure symptoms such as difficulty breathing and poor feedingPoor weight gain and failure to thriveReduced movement or activity levels
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)
Treatments
No FDA-approved treatments are currently listed for Lethal left ventricular non-compaction-seizures-hypotonia-cataract-developmental delay syndrome.
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Specialists
View all specialists →No specialists are currently listed for Lethal left ventricular non-compaction-seizures-hypotonia-cataract-developmental delay 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 left ventricular non-compaction-seizures-hypotonia-cataract-developmental delay syndrome.
Community
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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 genetic testing do you recommend to confirm the diagnosis, and how long will results take?,What are the signs that my child's heart condition is getting worse, and when should I go to the emergency room?,What anti-seizure medications are you recommending and what are the side effects to watch for?,Should we be referred to a palliative care team, and what does that involve?,Are there any research studies or registries we can participate in to help advance understanding of this disease?,What early intervention therapies should we start, and how do we access them?,What does the expected disease course look like for my child based on what is currently known?
Common questions about Lethal left ventricular non-compaction-seizures-hypotonia-cataract-developmental delay syndrome
What is Lethal left ventricular non-compaction-seizures-hypotonia-cataract-developmental delay syndrome?
Lethal left ventricular non-compaction-seizures-hypotonia-cataract-developmental delay syndrome is an extremely rare and severe genetic condition that affects multiple body systems, most critically the heart and brain. The disease is sometimes referred to by its Orphanet code ORPHA:478049. In this condition, the left side of the heart does not develop properly — the heart muscle stays in a spongy, unfinished state instead of becoming firm and compact as it normally should. This is called 'left ventricular non-compaction' (LVNC), and it makes it very hard for the heart to pump blood effectively
How is Lethal left ventricular non-compaction-seizures-hypotonia-cataract-developmental delay syndrome inherited?
Lethal left ventricular non-compaction-seizures-hypotonia-cataract-developmental delay syndrome follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Lethal left ventricular non-compaction-seizures-hypotonia-cataract-developmental delay syndrome typically begin?
Typical onset of Lethal left ventricular non-compaction-seizures-hypotonia-cataract-developmental delay syndrome is neonatal. Age of onset can vary across affected individuals.