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IEMbase 0510: CYP11A1-related side-chain cleavage enzyme deficiency

Scope

Field Value
IEMbase ID 510
Nosology 15.7.01.02
Gene CYP11A1
External IDs OMIM:118485; ORPHA:289548
Generated mapping UNMAPPED; best candidate Nonketotic_Hyperglycinemia.yaml
Candidate DisMech targets No exact local target found
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents this as CYP11A1-related side-chain cleavage enzyme deficiency, with alternate labels desmolase deficiency and P450scc deficiency. No treatments are listed. The biochemical rows show a salt-wasting adrenal pattern: potassium is high or very high from the neonatal period onward, and sodium is very low in the neonatal/infant period with persistent low or low-normal values later.

Clinical-characteristic rows include adrenal insufficiency, frequent ambiguous genitalia in 46,XY individuals, and very frequent cryptorchidism. Adrenal hyperplasia is recorded as normal, which helps distinguish this from some other congenital adrenal hyperplasia presentations.

DisMech phenotype coverage

No exact local CYP11A1/P450scc target was found. The generated candidate Nonketotic_Hyperglycinemia.yaml is invalid: it covers GLDC/AMT/GCSH glycine cleavage deficiency with glycine accumulation, neonatal encephalopathy, seizures, hypotonia, and apnea, not adrenal steroidogenesis or sex-development findings.

Congenital_Adrenal_Hyperplasia.yaml provides useful pathway context for steroidogenesis disorders, and Chronic_Primary_Adrenal_Insufficiency.yaml provides syndrome context for adrenal failure with electrolyte disturbance. The local CAH entry includes common enzyme defects such as CYP21A2, CYP11B1, CYP17A1, HSD3B2, and STAR, but it does not include CYP11A1/desmolase/P450scc side-chain cleavage deficiency.

Concordance and completeness

Judgement: true local gap.

The IEMbase profile is specific for CYP11A1 steroid side-chain cleavage failure: salt-wasting adrenal insufficiency, potassium/sodium abnormalities, and 46,XY undervirilization/cryptorchidism. Local adrenal entries give context but not the gene-specific disease.

Curation actions

  • Track CYP11A1-related P450scc deficiency as a local steroidogenesis gap.
  • Reject Nonketotic_Hyperglycinemia.yaml as a lexical false candidate.
  • If curated, decide whether CYP11A1 belongs as a new subtype under congenital adrenal hyperplasia or as a linked adrenal-insufficiency/sex-development entry; preserve the normal adrenal hyperplasia row as a differentiating prompt.