IEMbase 0151: TPMT-related thiopurine S-methyltransferase deficiency
Scope
| Field | Value |
|---|---|
| IEMbase ID | 151 |
| Nosology | 16.2.16.01 |
| Gene | TPMT |
| External IDs | OMIM:610460; OMIM:187680; ORPHA:413687 |
| Generated mapping | UNMAPPED |
| Candidate DisMech targets | No valid TPMT target found; GAMT deficiency candidate is false |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents this as TPMT-related thiopurine S-methyltransferase deficiency, with alternate label poor metabolism of thiopurines 1. Treatability is marked unknown.
The cached IEMbase phenotype signal is minimal: the only clinical row records decreased tolerance to thiopurines. No biochemical analyte panel or broader multisystem phenotype is listed in the extracted symptom table.
DisMech phenotype coverage
No local TPMT deficiency or thiopurine pharmacogenetic-trait entry was found. TPMT appears only as pharmacogenetic screening context in diseases where thiopurine therapy may be used. That is not disease-level coverage for a TPMT metabolism trait.
The generated best candidate, guanidinoacetate methyltransferase deficiency, is not valid. GAMT is a creatine-biosynthesis disorder and is unrelated to TPMT thiopurine methylation.
Concordance and completeness
Judgement: unmapped scope-review item.
This is not a typical multisystem inborn-error disease record in the local KB sense; it is primarily a pharmacogenetic decreased-drug-tolerance trait. Current DisMech has no canonical slot or disease entry for this trait. Whether it should be curated as a disorder, treatment-toxicity modifier, or left outside disease scope requires a scope decision.
Curation actions
- Keep this record unmapped.
- Reject the GAMT deficiency candidate as a methyltransferase lexical false positive.
- Before adding a standalone entry, decide whether TPMT poor thiopurine metabolism belongs in DisMech as a pharmacogenetic trait or as treatment-risk context attached to thiopurine-using disease entries.