congenital bile acid synthesis defect 1
Findings
No curated finding names congenital bile acid synthesis defect 1 yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Congenital bile acid synthesis defect type 1 (BAS defect type 1) is the most common anomaly of bile acid synthesis characterized by variable manifestations of progressive cholestatic liver disease, and fat malabsorption.
Definition from the Mondo Disease Ontology (MONDO:0011906), read 2026-09-29. CC BY 4.0.
- Inheritance
- Autosomal recessive inheritance
- Onset and course
- Neonatal onset
HPO, annotations 2026-09-02
Features
23 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- Reduced C27 3beta-HSD activity in cultured fibroblastsHPOHP:6000825
- 1 of 1 reported patient
- HepatomegalyHPOHP:0002240
- 12 of 13 reported patients
- Very frequent (80% to 99% of cases)
- Biliary tract abnormalityHPOHP:0001080
- Very frequent (80% to 99% of cases)
- Elevated circulating hepatic transaminase concentrationHPOHP:0002910
- Very frequent (80% to 99% of cases)
- Failure to thriveHPOHP:0001508
- Very frequent (80% to 99% of cases)
- JaundiceHPOHP:0000952
- 7 of 13 reported patients
- Very frequent (80% to 99% of cases)
Show the remaining 11
- Abnormal bleedingHPOHP:0001892
- Occasional (5% to 29% of cases)
- CirrhosisHPOHP:0001394
- Occasional (5% to 29% of cases)
- NyctalopiaHPOHP:0000662
- Occasional (5% to 29% of cases)
- OsteoporosisHPOHP:0000939
- Occasional (5% to 29% of cases)
- Peripheral neuropathyHPOHP:0009830
- Occasional (5% to 29% of cases)
- PruritusHPOHP:0000989
- Occasional (5% to 29% of cases)
Genes
1 gene
Germline variants in the gene encoding each protein, as classified by GenCC submitters, each in their own words. Limited, disputed and refuted submissions are listed too.
- HSD3B7HGNC:18324
- Definitive · ClinGen · Autosomal recessive · 2022
- Definitive · G2P · Autosomal recessive · 2015
- Strong · Labcorp Genetics (formerly Invitae) · Autosomal recessive · 2023
- Strong · PanelApp Australia · Autosomal recessive · 2025
- Supportive · Orphanet · Autosomal recessive · 2021
Where it sits
Other names
7 names
Resolves to: congenital bile acid synthesis defect 1
- Also called
- 3-beta-hydroxy-delta-5-C27-steroid oxidoreductase deficiency type 1BASD1bile acid synthesis defect, congenital, type 1CBAS1congenital bile acid synthesis defect caused by mutation in HSD3B7congenital bile acid synthesis defect type 1HSD3B7 congenital bile acid synthesis defect