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IEMbase 0079: GPHN-related molybdenum cofactor deficiency C

Scope

Field Value
IEMbase ID 79
Nosology 21.10.03.01
Gene GPHN
External IDs OMIM:603930
Generated mapping UNMAPPED
Candidate DisMech targets None
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents this as autosomal recessive GPHN-related molybdenum cofactor deficiency C, with alternate labels MoCo deficiency complementation group C, gephyrin deficiency, and MOCD-C. Treatability is marked unknown.

The characteristic biochemical signal includes plasma cystine, plasma homocysteine, plasma S-sulfocysteine, sulfite in plasma or urine, taurine in plasma or urine, plasma uric acid, and xanthine in plasma or urine. Additional rows include alpha-AASA, pipecolic acid, pyridoxal 5-phosphate, urinary S-sulfocysteine, urinary CPMP, and urinary urothione.

Characteristic clinical rows include cortical blindness, feeding difficulty, global developmental delay, extremity hypertonia, lens dislocation, microcephaly, nephrolithiasis, 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 GPHN-related molybdenum cofactor deficiency C.

The local KB does mention GPHN in Hereditary_Hyperekplexia.yaml, where it is a gene associated with inhibitory-synapse scaffolding and hyperekplexia. That is a gene-symbol collision for this IEMbase record, not a valid disease match. MOCD-C is a molybdenum cofactor disorder with sulfite/xanthine/uric-acid abnormalities, lens dislocation, nephrolithiasis, and severe neurologic disease.

Concordance and completeness

Judgement: true local gap.

This record belongs with future molybdenum cofactor deficiency coverage rather than with the existing hyperekplexia entry. It is the likely sibling of the MOCS1/MOCD-A and MOCS2/MOCD-B records in the same IEMbase block.

Curation actions

  • Keep this IEMbase record unmapped for now.
  • Add GPHN/MOCD-C to a future molybdenum cofactor deficiency entry or grouping.
  • Guard against gene-only mapping to hereditary hyperekplexia; the mechanism and biochemical signature are distinct.