National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Congenital bile acid synthesis defect, type 1



Other Names:
CBAS1; 3-alpha beta-hydroxy-delta-5-c27-steroid oxidoreductase, deficiency of; 3-beta-hydroxy-delta-5-C27-steroid oxidoreductase deficiency; CBAS1; 3-alpha beta-hydroxy-delta-5-c27-steroid oxidoreductase, deficiency of; 3-beta-hydroxy-delta-5-C27-steroid oxidoreductase deficiency; Congenital bile acid synthesis defect type 1; BASD1 See More
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The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.
orphanet

Orpha Number: 79301

Definition
Congenital bile acid synthesis defect type 1 (BAS defect type 1) is the most common anomaly of bile acid synthesis (see this term) characterized by variable manifestations of progressive cholestatic liver disease, and fat malabsorption.

Epidemiology
Prevalence is unknown but may be around 1-9/1,000,000 for overall BAS defects, excluding cerebrotendinous xanthomatosis.

Clinical description
The clinical presentation is heterogeneous, however most patients present with features of neonatal cholestasis. Clinical features include hepatomegaly with or without splenomegaly, jaundice, fat and fat-soluble vitamin malabsorption, and mild steatorrhea. In most cases, pruritus is absent. Liver function tests present elevated serum transaminases (AST, ALT), conjugated hyperbilirubinemia, and normal gamma-GT. The liver histology shows inflammation, giant cells, evidence of cholestasis, and variable degrees of liver fibrosis. The clinical course of early-onset disease is heterogeneous with some patients resolving jaundice and being identified later in life, or with more fulminant disease that results in death or requires liver transplantation at an early age. The disorder may also present as late-onset chronic cholestasis. In such patients, liver disease is not always evident and patients may have fat-soluble vitamin malabsorption with rickets, corrected by vitamin supplementation, and/or other complications including bleeding diathesis (hematochezia or intracranial bleeding), neuroaxonal dystrophy and night blindness. Serum liver enzymes are initially often normal but later show increases with progression of liver disease to fibrosis. Children and adolescents may also present with extensive fibrosis and/or cirrhosis.

Etiology
The disease is caused by a mutation in the gene encoding 3-beta-hydroxy-delta-5-C27 steroid oxidoreductase (HSD3B7, 16p12-p11.2). Transmission is autosomal recessive.

Diagnostic methods
Diagnosis is based on detection of sulfate and glycosulfate conjugates of 3-beta-hydroxy-delta-5 bile acids, which are the signature metabolites of this bile acid defect, on liquid secondary ionization mass spectrometry (LSIMS) analysis of urine. Gas chromatography - mass spectrometry (GC-MS) or electroscopy and tandem mass spectrometry may also be used.

Differential diagnosis
Differential diagnoses include progressive familial intrahepatic cholestasis, diseases that present with neonatal cholestasis, which includes alpha-1-antitrypsin deficiency of ZZ phenotype, Alagille syndrome, biliary atresia, cystic fibrosis, and metabolic diseases (tyrosinemia type I, galactosemia, hereditary fructose intolerance) (see these terms), diseases that present with fat and fat soluble vitamin malabsorption, including other liver diseases, and intestinal disease, or diseases that present with growth failure.

Antenatal diagnosis
Antenatal diagnosis can be made on embryonic tissue obtained when there has been a previously identified sibling. Urine LSIMS in a suspect infant can confirm the diagnosis in the first neonatal days.

Management and treatment
Treatment is based on oral administration of cholic acid which leads to gradual resolution of biochemical and histologic abnormalities and prevents progression of the disease, even in cases with hepatic fibrosis and cirrhosis. Cholic acid therapy stimulates bile flow and suppresses synthesis of atypical bile acids and production of toxic intermediates via the bile acid pathway linked to the pathogenesis of disease.

Prognosis
With early treatment the long-term prognosis is excellent.

Visit the Orphanet disease page for more resources.
Last updated: 1/1/2011

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Showing of 27 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Biliary tract abnormality 0001080
Elevated hepatic transaminase
High liver enzymes
0002910
Failure to thrive
Faltering weight
Weight faltering
[ more ]
0001508
Hepatomegaly
Enlarged liver
0002240
Jaundice
Yellow skin
Yellowing of the skin
[ more ]
0000952
Malabsorption
Intestinal malabsorption
0002024
Neonatal cholestatic liver disease 0006566
30%-79% of people have these symptoms
Abnormality of coagulation 0001928
Gastrointestinal hemorrhage
Gastrointestinal bleeding
0002239
Splenomegaly
Increased spleen size
0001744
5%-29% of people have these symptoms
Cirrhosis
Scar tissue replaces healthy tissue in the liver
0001394
Nyctalopia
Night blindness
Night-blindness
Poor night vision
[ more ]
0000662
Osteoporosis 0000939
Peripheral neuropathy 0009830
Pruritus
Itching
Itchy skin
Skin itching
[ more ]
0000989
Percent of people who have these symptoms is not available through HPO
Abnormality of the coagulation cascade 0003256
Acholic stools
Clay colored stools
0011985
Autosomal recessive inheritance 0000007
Diarrhea
Watery stool
0002014
Giant cell hepatitis 0200084
Hepatic failure
Liver failure
0001399
Hyperbilirubinemia
High blood bilirubin levels
0002904
Hypocholesterolemia
Decreased circulating cholesterol level
0003146
Intrahepatic cholestasis 0001406
Neonatal onset 0003623
Rickets
Weak and soft bones
0002748
Steatorrhea
Fat in feces
0002570
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Last updated: 7/1/2020

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

FDA-Approved Treatments

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.

  • cholic acid (Brand name: Cholbam) - Manufactured by Asklepion Pharmaceuticals, LLC
    FDA-approved indication: Treatment of bile acid synthesis disorders due to single enzyme defects and as adjunctive treatment of peroxisomal disorders including Zellweger spectrum disorders in patients who exhibit manifestations of liver disease, steatorrhea or complications from decreased fat soluble vitamin absorption.
    National Library of Medicine Drug Information Portal

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources


Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Congenital bile acid synthesis defect, type 1. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • Genetics Home Reference (GHR) contains information on Congenital bile acid synthesis defect, type 1. This website is maintained by the National Library of Medicine.

In-Depth Information

  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Congenital bile acid synthesis defect, type 1. Click on the link to view a sample search on this topic.

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