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IEMbase 0602: DHDDS-related dehydrodolichyl diphosphate synthase deficiency

Scope

Field Value
IEMbase ID 602
Nosology 18.4.01.04
Gene DHDDS
External IDs OMIM:613861; OMIM:608172; ORPHA:442835
Generated mapping CANDIDATE; EYS_Related_Retinitis_Pigmentosa.yaml
Candidate DisMech targets None exact
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents DHDDS-related dehydrodolichyl diphosphate synthase deficiency, labelled DHDDS-CDG and retinitis pigmentosa 59. The record is autosomal recessive, classified under disorders of dolichol biosynthesis and activation, has unknown treatability, and has no treatment rows.

The record has normal serum sialotransferrins as its only biochemical row. Clinical rows include retinitis pigmentosa, epilepsy, intellectual disability, ataxia, dystonia, hypotonia, micropenis, and acute renal failure.

DisMech phenotype coverage

EYS_Related_Retinitis_Pigmentosa.yaml is a false-positive generated candidate. It models EYS/RP25, a photoreceptor structural/ciliary retinitis pigmentosa caused by the EYS gene. It does not represent DHDDS, dolichol-pathway dehydrodolichyl diphosphate synthase deficiency, CDG biology, or the extra-ocular epilepsy, intellectual-disability, movement, endocrine, and renal features in IEMbase.

Other local retinitis-pigmentosa entries provide final-common photoreceptor degeneration context only. No exact DHDDS-CDG / RP59 target was identified.

Concordance and completeness

Judgement: true local gap; reject EYS-related retinitis pigmentosa as exact coverage.

The candidate captures a shared retinitis-pigmentosa phenotype but fails the gene, pathway, and multisystem checks. IEMbase 0602 is a dolichol-biosynthesis CDG/retinal-neurologic disease, not an EYS photoreceptor structural disorder.

Curation actions

  • Create or identify an exact DHDDS-CDG / retinitis pigmentosa 59 target before import.
  • Reject EYS_Related_Retinitis_Pigmentosa.yaml as an exact mapping.
  • Preserve normal sialotransferrins, retinitis pigmentosa, epilepsy, intellectual disability, ataxia, dystonia, hypotonia, micropenis, and acute renal-failure prompts.