ORPHA:79095
Congenital bile acid synthesis defect type 4
Also known as: 2-methylacyl-CoA racemase deficiency · AMACR deficiency · Alpha-methyl-acyl-CoA racemase deficiency · BASD4 · Liver disease-retinitis pigmentosa-polyneuropathy-epilepsy syndrome
Query health: suspect — Only one of 3 strategies returned hits (phrase).
Publications
85
54.3th percentile
Trials
0
Interventional, condition-specific
Researchers
460
Distinct authors in sample
Gene link
AMACR
Strong
Readiness
2/6
Stages with a signal
Clinical definition (Orphanet)
bile acid synthesis defect type 4 (BAS defect type 4) is an anomaly of bile acid synthesis characterized by mild cholestatic liver disease, fat malabsorption and/or neurological disease.
How rare: <1 / 1 000 000 — fewer than one in a million. In a city the size of Kolkata, that might mean on the order of fifteen people.
Cross-references
Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.
- MONDO:0008967
- MeSH:C535444
- OMIM:214950
- UMLS:C1858328
Additional Mondo synonyms (6)
BAS defect type 4 · CBAS4 · bile acid synthesis defect, congenital, type 4 · congenital bile acid synthesis defect 4 · congenital bile acid synthesis defect type 4 · liver disease-retinitis pigmentosa-polyneuropathy-epilepsy syndrome
Research stages
Trial readiness signals
Where this condition sits on an open-data research pipeline — not how close a treatment is, and not medical advice. Empty stages often mean “not in these databases under this Mondo ID,” not “impossible.”
2/6 stages with a signal
No matched interventional trial; the gene is known and literature exists — preclinical or natural-history work may still be the practical next step.
- Gene identifiedPresent
Strong — AMACR
- LiteraturePresent
85 matched papers (53 in last 10 years) Source
- Phenotype characterisedNot checked
Not yet enriched from Monarch / HPO
- Animal modelNot checked
Not yet enriched from Monarch / Alliance
- Orphan designationNot checked
FDA/EMA orphan-drug designation not enriched yet
- Interventional trialNot found
No matched interventional trial under our ClinicalTrials.gov rules
Biology
Genes and phenotypes
Gene–disease validity from GenCC, plus phenotypes and animal models joined from Monarch Initiative via Mondo ID — not a clinical diagnosis aid.
Do we know what causes it?
Yes — we know a specific gene responsible (AMACR).
GenCC classification: Strong.
Phenotypes (Monarch / HPO)
Not enriched in this build — Monarch phenotype joins were not run for this record.
Animal models (Monarch / Alliance)
Not enriched in this build.
Literature
Is anyone studying this?
85
85 papers have ever been published on this condition (under this name). For scale, breast cancer has over 700,000. Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=5449) is 41.
85 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 41 (publications denominator n=5449).
53 in the last 10 years · high confidence · 54.3th percentile (publications denominator)
Phrase hits: 85 · MeSH hits: 0
Who's working on it?
460
Distinct author names in 85 sampled papers — named people below.
Who's working on it?
No interventional trial matched this name; these authors publish on it in the sampled literature — a practical starting point for contact.
- 01Ferdinandusse S10 papers · 2025
Laboratory Genetic Metabolic Diseases, Laboratory Division, Departments of Paediatrics and Clinical Chemistry, Academic Medical Center, Emma Children's Hospital, University of Amsterdam Amsterdam, Netherlands.
Papers in Europe PMC - 02Wanders RJ8 papers · 2016
Laboratory Genetic Metabolic Diseases, Laboratory Division, Departments of Paediatrics and Clinical Chemistry, Academic Medical Center, Emma Children's Hospital, University of Amsterdam Amsterdam, Netherlands.
Papers in Europe PMC - 03Vaz FM6 papers · 2026
Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
Papers in Europe PMC - 04Engelen M5 papers · 2025
Department of Paediatric Neurology, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Meibergdreef 9, PO BOX 22660, 1105 AZ, Amsterdam, The Netherlands. m.engelen@amc.uva.nl.
Papers in Europe PMC - 05Hollak CEM4 papers · 2025
Medicine for Society, Platform at Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
Papers in Europe PMC - 06Waterham HR4 papers · 2018
Laboratory Genetic Metabolic Diseases, Laboratory Division, Departments of Paediatrics and Clinical Chemistry, Academic Medical Center, Emma Children's Hospital, University of Amsterdam Amsterdam, Netherlands.
Papers in Europe PMC - 07Baes M3 papers · 2021
Department of Pharmaceutical and Pharmacological Sciences, Cell Metabolism, KU Leuven-University of Leuven, B-3000, Leuven, Belgium.
Papers in Europe PMC - 08Hiltunen JK3 papers · 2015
Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5400, FI-90014, Finland; Biocenter Oulu, University of Oulu, Finland.
Papers in Europe PMC - 09Kemper EM3 papers · 2025
Department of Pharmacy and Clinical Pharmacology, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
Papers in Europe PMC - 10Klouwer FCC3 papers · 2025
Department of Pediatric Neurology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
Papers in Europe PMC
Clinical research
Is a treatment being tested?
0
interventional trials for this specific condition
No interventional trial testing a treatment matched this specific condition name on ClinicalTrials.gov (observational studies and pan-disease registries are listed separately when present).
Data as of 27 July 2026
No matched interventional trials. This is true for 73% of diseases in the trials denominator (5114 of 7003). Here are the researchers publishing on it.
high confidence · 36.5th percentile (trials denominator)
Recruiting interventional trials
From the matched ClinicalTrials.gov set
No interventional trial testing a treatment was found for this specific condition name on ClinicalTrials.gov.
Broader category congenital bile acid synthesis defect also has no matched interventional trial. See who's working on it — people publishing on this disease are often the practical next contact when no trial is listed.
Broader category: congenital bile acid synthesis defect
0
Interventional trials for the parent category, exclusive of NCT IDs already counted above. Eligibility for this subtype is not guaranteed.
Parent-category matching found a broader label but no interventional trials under it. How we count trials.
Where to find support
We do not yet link condition-specific patient organisations. These umbrella groups support undiagnosed and ultra-rare families:
India — NPRD
Last verified 2026-07-26This ORPHAcode is not on our curated NPRD list (direct or Mondo-parent match). That does not decide clinical eligibility; families in India should ask a notified Centre of Excellence about current coverage.
Hand-curated for this project. ORPHAcode mappings are best-effort and may be incomplete or imprecise for umbrella categories. Parent (Mondo) matches mean the policy lists a broader category — confirm eligibility with a Centre of Excellence. Financial entitlements summarised from public policy statements and may change. This is not official government guidance.
How we counted this
Europe PMC query (preferred label + any corrected label + Orphanet and Mondo exact synonyms, stoplisted; unioned with resolved MeSH labels when available). UMLS / OMIM / NCIT cross-references are stored on the overview but are not added to the query string.
"Congenital bile acid synthesis defect type 4" OR "2-methylacyl-CoA racemase deficiency" OR "AMACR deficiency" OR "Alpha-methyl-acyl-CoA racemase deficiency" OR "BASD4" OR "Liver disease-retinitis pigmentosa-polyneuropathy-epilepsy syndrome" OR "BAS defect type 4" OR "CBAS4" OR "bile acid synthesis defect, congenital, type 4" OR "congenital bile acid synthesis defect 4"
MeSH descriptor terms unioned into the query: Bile acid synthesis defect, congenital, 4
ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):
"Congenital bile acid synthesis defect type 4" OR "2-methylacyl-CoA racemase deficiency" OR "AMACR deficiency" OR "Alpha-methyl-acyl-CoA racemase deficiency" OR "BASD4" OR "Liver disease-retinitis pigmentosa-polyneuropathy-epilepsy syndrome" OR "BAS defect type 4" OR "CBAS4" OR "bile acid synthesis defect, congenital, type 4" OR "congenital bile acid synthesis defect 4" OR "Bile acid synthesis defect, congenital, 4" OR "AMACR"
Recall-expansion terms: AMACR
Study-type breakdown: 0 interventional · 0 observational · 0 expanded access. Only interventional studies enter the trial headline.
Parent-category trials query:
"congenital bile acid synthesis defect"
Query health: suspect — strategies attempted: phrase, mesh, recall-expansion; with hits: phrase
Run this search on ClinicalTrials.gov
Confidence reasoning
- Preferred label is multi-word and distinctive
- No synonyms dropped by stoplist
- No label/synonym collisions with other diseases in this corpus
Ingested 2026-07-27T01:55:57.394Z