IEMbase 0051: SLC7A7-related lysinuric protein intolerance
Scope
| Field | Value |
|---|---|
| IEMbase ID | 51 |
| Nosology | 1.11.06.01 |
| Gene | SLC7A7 |
| External IDs | OMIM:222700 |
| Generated mapping | UNMAPPED |
| Candidate DisMech targets | None; fuzzy neighbor Hartnup_Disease.yaml |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents this as autosomal recessive SLC7A7-related lysinuric protein intolerance, also named dibasic aminoaciduria type 2 or LPI. Treatability is marked yes. The listed prevalence is 1:60,000 in Italy and Finland and less than 1:1,000,000 in most other places.
The biochemical profile is broad and severe: increased blood ammonia, increased urinary orotic acid, increased urinary lysine with increased urinary arginine and ornithine, low-to-normal plasma arginine/lysine/ornithine after infancy, increased plasma alanine, citrulline, glutamine, glycine, and proline, plus normal-to-increased LDH and increased ferritin.
The characteristic clinical feature is possible hyperammonemic coma. Additional clinical features include protein intolerance, vomiting, diarrhea, hepatosplenomegaly, pulmonary alveolar proteinosis, interstitial chest radiograph changes, respiratory insufficiency with muscle weakness or diaphragm paralysis, hemophagocytic lymphohistiocytosis/macrophage activation syndrome, hemophagocytosis, glomerulonephritis, hypertension, end-stage renal failure, osteoporosis, impaired bone growth, combined hyperlipidemia, intellectual disability, and sparse hair.
DisMech phenotype coverage
There is no local DisMech entry for SLC7A7-related lysinuric protein intolerance.
The fuzzy neighbor Hartnup_Disease.yaml is a false positive. Hartnup disease
is SLC6A19/B0AT1 neutral amino acid transport disease with a
tryptophan/nicotinamide and pellagra-like neurocutaneous mechanism. LPI is an
SLC7A7 cationic/dibasic amino acid transport disorder with systemic nitrogen
handling consequences, hyperammonemia, protein intolerance, pulmonary, immune,
renal, and bone complications.
This record also should not be folded into Cystinuria.yaml despite dibasic
amino-acid urinary abnormalities. Cystinuria is SLC3A1/SLC7A9 cystine/dibasic
amino-acid transport disease dominated by cystine stones, whereas IEMbase ID 51
is a systemic LPI phenotype with hyperammonemia and multisystem complications.
Concordance and completeness
Judgement: true unmapped record and high-value future curation target.
The generated unmapped status is appropriate because local DisMech lacks an LPI entry. The severity and treatability make this much more than a benign aminoaciduria. Its distinguishing features are SLC7A7, cationic amino acid transport, hyperammonemia, urinary orotic acid, protein intolerance, pulmonary alveolar proteinosis, HLH/macrophage activation, and renal/bone involvement.
Curation actions
- Keep the record unmapped for now.
- Do not map to Hartnup disease or cystinuria.
- Prioritize a future standalone lysinuric protein intolerance entry because the phenotype is severe, treatable, and mechanistically distinct from the local aminoaciduria entries.