Overview
Familial intrahepatic cholestasis type 1 (FIC1 disease), also known as Byler disease or Progressive Familial Intrahepatic Cholestasis type 1 (PFIC1), is a rare inherited liver disorder. In this condition, the liver has trouble moving bile — a digestive fluid — out of liver cells and into the bile ducts. When bile builds up inside liver cells, it causes damage over time. The disease is caused by changes (mutations) in the ATP8B1 gene, which provides instructions for a protein that helps keep bile flowing properly. People with this condition often develop symptoms in infancy or early childhood. The most noticeable sign is severe, persistent itching (called pruritus) caused by bile acids building up in the blood and skin. Yellowing of the skin and eyes (jaundice) is also common. Over time, the liver can become scarred (cirrhosis), which can lead to liver failure if not treated. Treatment focuses on relieving symptoms and slowing liver damage. Medications can help reduce bile buildup and itching. A surgical procedure called partial biliary diversion, which reroutes some bile away from the body, can help some patients. Liver transplantation may be needed in severe cases, though it does not always fully resolve all symptoms. There is currently no cure, and ongoing specialist care is essential for managing this lifelong condition.
Key symptoms:
Severe, persistent itching all over the bodyYellowing of the skin and whites of the eyes (jaundice)Poor growth and failure to gain weight normallyFatty, foul-smelling stools (steatorrhea)Enlarged liver and spleenFatigue and low energyDiarrhea (which can be a distinguishing feature compared to other similar diseases)Vitamin deficiencies, especially vitamins A, D, E, and KBone thinning (rickets or osteoporosis) due to poor vitamin absorptionHearing loss in some patientsPancreatitis (inflammation of the pancreas) in some casesLiver scarring (cirrhosis) in advanced diseaseLiver failure if untreated
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Infantile
Begins in infancy, roughly 1 month to 2 years old
FDA & Trial Timeline
1 eventNational Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) — NA
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Rare hepatic disease.
View clinical trials →Clinical Trials
View all trials with filters →No actively recruiting trials found for Rare hepatic disease at this time.
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Rare Disease Specialist
Rare Disease Specialist
Treatment Centers
8 centersNational Institutes of Health Clinical Center
📍 Bethesda, Maryland
👤 Payal P Khincha, M.D.
👤 Christopher Grunseich, M.D.
Stanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🔬 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
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🏥 NORDBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
Travel Grants
No travel grants are currently matched to Rare hepatic disease.
Community
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Disease timeline:
New trial: Natural History, Pathogenesis and Outcome of Melorheostosis A Rare Osteosclerotic Disease
Phase NA trial recruiting.
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 stage is my child's liver disease at, and how quickly might it progress?,Is my child a candidate for partial biliary diversion surgery, and what are the risks and benefits?,Should we consider odevixibat (Bylvay) for managing the itching, and is it right for our situation?,When should we start thinking about liver transplantation, and what does that process look like?,What vitamins and nutritional supplements does my child need, and how do we monitor for deficiencies?,Should other family members be tested as carriers, and what does this mean for future pregnancies?,Are there any clinical trials or new treatments we should know about?
Common questions about Rare hepatic disease
What is Rare hepatic disease?
Familial intrahepatic cholestasis type 1 (FIC1 disease), also known as Byler disease or Progressive Familial Intrahepatic Cholestasis type 1 (PFIC1), is a rare inherited liver disorder. In this condition, the liver has trouble moving bile — a digestive fluid — out of liver cells and into the bile ducts. When bile builds up inside liver cells, it causes damage over time. The disease is caused by changes (mutations) in the ATP8B1 gene, which provides instructions for a protein that helps keep bile flowing properly. People with this condition often develop symptoms in infancy or early childhood.
How is Rare hepatic disease inherited?
Rare hepatic disease follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Rare hepatic disease typically begin?
Typical onset of Rare hepatic disease is infantile. Age of onset can vary across affected individuals.
Which specialists treat Rare hepatic disease?
12 specialists and care centers treating Rare hepatic disease are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.