IEMbase 0652: KYNU-related 3-hydroxykynureninase deficiency
Scope
| Field | Value |
|---|---|
| IEMbase ID | 652 |
| Nosology | 1.8.01.02 |
| Nosology code | IEM0162 |
| Gene | KYNU |
| External IDs | OMIM:605197; ORPHA:79155 |
| Generated mapping | UNMAPPED; weak candidate Hereditary_Orotic_Aciduria.yaml |
| Candidate DisMech targets | No exact local target |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents autosomal recessive KYNU-related 3-hydroxykynureninase deficiency, with alternate labels vertebral, cardiac, renal, and limb defects syndrome type 2 and xanthurenic aciduria.
Biochemical rows include increased urinary 3-hydroxykynurenine, kynurenine, and xanthurenic acid; increased plasma 3-hydroxykynurenine; and decreased plasma NAD+. Clinical rows include anteriorly placed anus, hypoplastic left heart, patent ductus arteriosus, rhizomelia, abnormal/delayed/absent speech, syndactyly, renal hypoplasia, short stature, and talipes.
DisMech phenotype coverage
Hereditary_Orotic_Aciduria.yaml is a lexical false candidate. It models
UMPS-related de novo pyrimidine synthesis failure, urinary orotic acid,
megaloblastic anemia, developmental delay, and uridine responsiveness. It does
not model KYNU, kynurenine-pathway flux, xanthurenic aciduria, NAD+ deficiency,
or the VCRL2 malformation pattern.
Targeted search did not find a local KYNU, 3-hydroxykynureninase deficiency, xanthurenic aciduria, or VCRL type 2 disease entry.
Concordance and completeness
Judgement: true local KYNU / VCRL2 gap; reject hereditary orotic aciduria as exact.
The generated candidate is an unrelated nucleotide-metabolism disorder. IEMbase points to a separate tryptophan/kynurenine-pathway malformation disorder with specific metabolite readouts and cardiac/renal/limb/developmental prompts.
Curation actions
- Keep this row unmapped until a KYNU / VCRL type 2 target exists.
- Do not map to
Hereditary_Orotic_Aciduria.yaml. - Preserve increased 3-hydroxykynurenine, kynurenine, xanthurenic acid, decreased NAD+, congenital heart findings, renal hypoplasia, rhizomelia, syndactyly, talipes, anteriorly placed anus, short stature, and speech prompts.