IEMbase 0125: CYP17A1-related 17,20-Lyase deficiency
Scope
| Field | Value |
|---|---|
| IEMbase ID | 125 |
| Nosology | 24.2.05.02 |
| Gene | CYP17A1 |
| External IDs | OMIM:202110; ORPHA:90796 |
| Generated mapping | UNMAPPED |
| Candidate DisMech targets | Partial mechanistic neighbor Congenital_Adrenal_Hyperplasia.yaml#17A-OHD; no standalone isolated 17,20-lyase deficiency target |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents this as CYP17A1-related 17,20-lyase deficiency, with alternate label P450c17 deficiency. Treatability is marked unknown.
The IEMbase signal is sparse. Characteristic biochemical rows include mildly increased or normal-to-high 17-OH-progesterone. The only extracted clinical row is cryptorchidism. No treatment rows are listed.
DisMech phenotype coverage
Congenital_Adrenal_Hyperplasia.yaml includes a 17A-OHD subtype and a
CYP17A1 17-hydroxylase/17,20-lyase deficiency mechanism. That local subtype is
appropriate for combined CYP17A1 deficiency with cortisol and sex-steroid
deficiency plus relative mineralocorticoid precursor excess.
The local CAH entry does not currently separate isolated 17,20-lyase deficiency from 17-alpha-hydroxylase deficiency. Its CYP17A1 coverage is broader and more mineralocorticoid/cortisol oriented than this IEMbase record.
Concordance and completeness
Judgement: generated unmapped result is a partial false negative, but the local target is only an umbrella/neighbor.
The best available local context is the CAH 17A-OHD subtype, because it is
the only local CYP17A1 disease branch. However, IEMbase 0125 appears to be the
isolated 17,20-lyase branch rather than the full 17-alpha-hydroxylase/17,20-lyase
deficiency profile. The IEMbase signal of cryptorchidism and mild
17-OH-progesterone elevation does not match the fuller local CAH
mineralocorticoid-excess profile closely enough to call it complete coverage.
Curation actions
- Do not create a hard standalone mapping to CAH without preserving the isolated 17,20-lyase nuance.
- Record
Congenital_Adrenal_Hyperplasia.yaml#17A-OHDas partial local context until a CYP17A1 isolated 17,20-lyase subtype or entry exists. - Consider future subtype splitting if DisMech needs to distinguish isolated 17,20-lyase deficiency from combined CYP17A1 CAH.