IEMbase 0078: MOCS2-related molybdopterin synthase deficiency
Scope
| Field | Value |
|---|---|
| IEMbase ID | 78 |
| Nosology | 21.10.02.01 |
| Gene | MOCS2 |
| External IDs | OMIM:603708 |
| Generated mapping | UNMAPPED |
| Candidate DisMech targets | Best fuzzy candidate Tetrahydrobiopterin_Deficiency.yaml#PTPS Deficiency |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents this as autosomal recessive MOCS2-related molybdopterin synthase deficiency, with alternate labels MoCo deficiency complementation group B and MOCD-B. Treatability is marked unknown.
The characteristic biochemical signal includes urinary cyclic pyranopterin monophosphate, plasma and urinary S-sulfocysteine, sulfite in plasma or urine, taurine in plasma or urine, plasma homocysteine, urinary trimethylamine, urinary xanthine, and plasma uric acid. Additional biochemical rows include alpha-AASA, pipecolic acid, pyridoxal 5-phosphate, cystine, and urothione.
Characteristic clinical rows include cortical blindness, dysmorphic features, dystonic cerebral palsy, feeding difficulty, global developmental delay, extremity hypertonia, axial hypotonia, lens dislocation, microcephaly, myoclonus, orobulbar dysfunction, tonic-clonic seizures, and exaggerated startle response.
No treatment rows are present in the cached IEMbase record.
DisMech phenotype coverage
No valid local DisMech target was found for MOCS2 or molybdenum cofactor deficiency type B.
The best fuzzy candidate, Tetrahydrobiopterin_Deficiency.yaml#PTPS Deficiency,
is a false positive. PTPS deficiency is a tetrahydrobiopterin biosynthesis
disorder involving PTS and monoamine-neurotransmitter or phenylalanine
metabolism. MOCS2-related MOCD-B is a molybdenum cofactor biosynthesis disorder
with sulfite/xanthine/uric-acid abnormalities and a severe neonatal neurologic
phenotype.
Concordance and completeness
Judgement: true local gap.
This record should remain unmapped until a molybdenum cofactor deficiency entry or grouping exists. The existing MOCS1/MOCD-A note reached the same conclusion for complementation group A, so MOCS2 should likely be handled as a sibling subtype under a shared MoCo-deficiency curation target.
Curation actions
- Keep this IEMbase record unmapped for now.
- Add future molybdenum cofactor deficiency coverage with at least MOCD-A/MOCS1, MOCD-B/MOCS2, and MOCD-C/GPHN subtype or gene-specific branches.
- Prioritize CPMP, S-sulfocysteine, sulfite, xanthine, uric-acid abnormalities, severe early neurologic disease, lens dislocation, and seizure phenotype rows.