IEMbase 0137: LTC4S-related Leukotriene C4 synthase deficiency
Scope
| Field | Value |
|---|---|
| IEMbase ID | 137 |
| Nosology | 14.3.05.01 |
| Gene | LTC4S |
| External IDs | OMIM:246530; ORPHA:79507 |
| Generated mapping | UNMAPPED |
| Candidate DisMech targets | No valid LTC4S/leukotriene C4 synthase deficiency target found |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents this as LTC4S-related leukotriene C4 synthase deficiency, with alternate label cysteinyl leukotriene synthase 4 deficiency and abbreviation LTC4D. Treatability is marked unknown.
Characteristic biochemical rows include normal-to-increased leukotriene B4 in CSF and plasma, decreased leukotriene C4 in CSF and plasma, decreased leukotriene D4 in CSF and plasma, and decreased leukotriene E4 in CSF, plasma, and urine. A non-characteristic row records normal RBC glutathione. Clinical rows include absent head control, abnormal EMG, progressive encephalopathy, facial dysmorphism, hypotonia, lack of facial expression, microcephaly, minimal spontaneous movements, no visual contact, perinatal death, symmetric leg extension, decreased tendon reflexes, abnormal EEG, failure to thrive, and psychomotor delay.
DisMech phenotype coverage
No local standalone LTC4S or cysteinyl leukotriene synthesis deficiency target was found. The generated HMG-CoA synthase deficiency neighbor is a lexical false positive around "synthase" and does not share the leukotriene pathway, gene, or phenotype.
Concordance and completeness
Judgement: true unmapped local disease gap.
The IEMbase record contains a specific leukotriene-profile signature plus a severe neurodevelopmental/perinatal phenotype. Current DisMech does not model this leukotriene biosynthesis disorder and should not map it to unrelated ketogenesis or HMG-CoA synthase disease.
Curation actions
- Keep this record unmapped.
- Reject HMG-CoA synthase deficiency as a candidate.
- Future curation should model LTC4S loss, cysteinyl leukotriene depletion, leukotriene B4 relative preservation/increase, severe encephalopathy, hypotonia, microcephaly, EEG/EMG abnormalities, failure to thrive, and perinatal lethality.