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IEMbase 0181: CYP7B1-related BASD type 3

Scope

Field Value
IEMbase ID 181
Nosology 14.8.03.01
Gene CYP7B1
External IDs OMIM:603711; ORPHA:100986
Generated mapping CANDIDATE; Inborn_Disorder_of_Bile_Acid_Synthesis.yaml#BASD Type 3
Candidate DisMech targets Inborn_Disorder_of_Bile_Acid_Synthesis.yaml#BASD Type 3
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents this as CYP7B1-related oxysterol 7alpha-hydroxylase deficiency, with alternate labels spastic paraplegia 5A and CYP7B1. Treatability is marked yes.

The biochemical rows include increased urinary 3beta-hydroxy-5-cholenoic acids, increased plasma 3beta-hydroxy-5-cholestenoic acid, increased plasma 27-hydroxycholesterol, positive CYP7B1 sequencing, increased ASAT/ALAT, increased alkaline phosphatase, normal gamma-GT, normal-to-increased prothrombin ratio, increased total and direct bilirubin, normal cholesterol, decreased glucose, and decreased vitamin E. Clinical rows include bile duct proliferation, bridging fibrosis, cholestasis, giant-cell hepatitis, periportal inflammation, hepatosplenomegaly, hypoglycemia, jaundice, liver failure, vitamin K responsive bleeding, progressive spastic paraplegia, cataract, optic atrophy, cerebellar ataxia, and cerebellar white matter MRI abnormalities. No treatment rows are listed.

DisMech phenotype coverage

Inborn_Disorder_of_Bile_Acid_Synthesis.yaml#BASD Type 3 is the correct target. The local subtype covers CYP7B1/oxysterol 7alpha-hydroxylase deficiency, impaired acidic pathway bile acid synthesis, accumulation of 3beta-hydroxy-Delta5 monohydroxy bile acids, severe infantile cholestasis and liver failure, later neurologic disease including spastic paraplegia, neuropathy, and ataxia, chenodeoxycholic acid treatment, and possible liver transplantation.

Concordance and completeness

Judgement: accept the generated candidate as the correct subtype mapping.

IEMbase and DisMech agree on CYP7B1, the BASD type 3/oxysterol 7alpha-hydroxylase identity, atypical 3beta-hydroxy bile acid intermediates, normal gamma-GT cholestasis, infantile hepatic disease, liver failure risk, and later spastic paraplegia or cerebellar involvement. IEMbase adds 27-hydroxycholesterol, glucose, vitamin E, ocular findings, and cerebellar MRI detail. DisMech includes treatment context that is absent from the IEMbase treatment rows.

Curation actions

  • Resolve this record to Inborn_Disorder_of_Bile_Acid_Synthesis.yaml#BASD Type 3.
  • Consider adding 27-hydroxycholesterol, hypoglycemia, vitamin E deficiency, optic atrophy, cataract, and cerebellar MRI abnormalities as subtype review targets.
  • Preserve the distinction from CYP7A1-related cholesterol 7alpha-hydroxylase deficiency.