IEMbase 0016: ARG1-related arginase 1 deficiency
Scope
| Field | Value |
|---|---|
| IEMbase ID | 16 |
| Nosology | 1.1.06.01 |
| Gene | ARG1 |
| External IDs | OMIM:207800 |
| Generated mapping | MAPPED by alias_exact:arg1 deficiency |
| Candidate DisMech targets | Arginase_Deficiency.yaml |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase distinguishes ARG1 deficiency from the earlier UCDs by making chronic spastic diplegia and developmental delay the characteristic clinical signal. Other listed features include seizures, vomiting, episodic confusion, ataxia, feeding difficulty/protein aversion, hepatopathy, and coagulopathy. Hyperammonemia is present but less extreme than in CPS1/OTC/ASS1/ASL records.
The biochemical profile centers on high plasma arginine with high glutamine and only mild to moderate ammonia elevation, plus low/normal urea and variably high citrulline, orotic acid, and transaminases. Treatments include protein-defined diet, glycerol phenylbutyrate, sodium benzoate, sodium phenylbutyrate, hemodialysis, peritoneal dialysis, and liver transplantation.
DisMech phenotype coverage
The generated mapping to Arginase_Deficiency.yaml is correct. DisMech covers
spastic paraparesis, spasticity, progressive spastic quadriplegia, seizures,
intellectual disability, severe intellectual disability, global developmental
delay, abnormal speech, EEG abnormality, growth retardation, encephalopathy,
hepatomegaly, hyperargininemia, diaminoaciduria, white-matter abnormality, and
microcephaly. Biochemical coverage includes plasma arginine, guanidino
compounds, ornithine, ammonia, erythrocyte arginase activity, and urea. Treatment
coverage includes diet, nitrogen scavengers, pegzilarginase enzyme replacement,
liver transplantation, antispasticity management, antiepileptic therapy, newborn
screening, and genetic counseling.
Concordance and completeness
Judgement: correct mapping and high concordance for the core phenotype. DisMech is substantially richer for chronic neurologic sequelae and therapy.
IEMbase adds protein aversion, episodic confusion/ataxia, coagulopathy, and dialysis modality detail. DisMech adds guanidino-compound neurotoxicity, white-matter pathology, severe intellectual disability, speech/EEG features, and pegzilarginase.
Curation actions
- Keep the generated mapping.
- Consider adding protein aversion and coagulopathy only if independent evidence supports them for ARG1 deficiency.
- No immediate mapping correction needed.