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IEMbase 0631: PGAP3-related hyperphosphatasia with mental retardation syndrome 4

Scope

Field Value
IEMbase ID 631
Nosology 18.3.00.20
Gene PGAP3
External IDs OMIM:615716; ORPHA:247262
Generated mapping UNMAPPED
Candidate DisMech targets None exact; CHIME_syndrome.yaml is a GPI-anchor pathway neighbor
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents PGAP3-related hyperphosphatasia with mental retardation syndrome 4 / PGAP3-CDG as an autosomal recessive disorder with unknown treatability and no treatment rows.

Biochemical rows include increased alkaline phosphatase in infancy/childhood and decreased GPI markers by flow cytometry. Clinical and characteristic rows include hypotonia, optional cleft palate, optional micrognathia, optional ataxia, epilepsy, and intellectual disability.

DisMech phenotype coverage

No exact PGAP3/HPMRS4 entry was identified. CHIME_syndrome.yaml is a neighboring GPI-anchor biosynthesis disease caused by PIGL. It is useful pathway context but not an exact PGAP3 disease target.

Concordance and completeness

Judgement: true local gap.

The generated CHIME candidate should be rejected as exact because it reflects shared GPI-anchor biology and neurodevelopmental overlap, not shared gene or disease identity.

Curation actions

  • Do not map to PIGL-related CHIME syndrome.
  • Curate PGAP3/HPMRS4 as a separate GPI-anchor maturation disorder if selected.
  • Preserve alkaline phosphatase, decreased GPI-marker flow cytometry, hypotonia, epilepsy, intellectual disability, ataxia, cleft-palate, and micrognathia prompts.