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IEMbase 0598: GMPPA-related GDP-mannose pyrophosphorylase B deficiency

Scope

Field Value
IEMbase ID 598
Nosology 18.4.01.03
Gene GMPPA
External IDs OMIM:615510; ORPHA:869
Generated mapping UNMAPPED; best candidate CHIME_syndrome.yaml
Candidate DisMech targets None exact
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents GMPPA-related GDP-mannose pyrophosphorylase B deficiency (CDG), with alternate labels GMPPA-CDG, alacrima-achalasia-mental retardation syndrome, and AAMR. The record is autosomal recessive, classified under disorders of multiple glycosylation pathways, has unknown treatability, and has no treatment rows.

The biochemical row reports normal serum sialotransferrins. Clinical rows include facial dysmorphism, growth retardation, impaired hearing, postural hypotension, hypotonia, prominent forehead, protruding chin, short philtrum, thin lips with downturned mouth corners, triangular/asymmetric facies, achalasia, alacrima, developmental delay, dysphagia, gait disturbance, intellectual disability, ocular abnormalities, and regurgitation.

DisMech phenotype coverage

CHIME_syndrome.yaml is a false-positive generated candidate. CHIME models PIGL-related GPI-anchor biosynthesis disease with coloboma, congenital heart defects, ichthyosiform dermatosis, intellectual disability, ear anomalies, and seizures. It does not represent GMPPA, GDP-mannose pyrophosphorylase biology, AAMR, achalasia, alacrima, postural hypotension, or normal transferrin glycosylation.

The local knowledge base has broader glycosylation and alacrima context in other entries, but no exact GMPPA/AAMR target was identified.

Concordance and completeness

Judgement: true local gap; reject CHIME syndrome as exact coverage.

The generated candidate shares neurodevelopmental, hearing, and facial phenotype language, but gene, pathway, cardinal clinical triad, and biochemical pattern differ. IEMbase should be curated as GMPPA/AAMR rather than a GPI-anchor or CHIME-spectrum disorder.

Curation actions

  • Create or identify an exact GMPPA-CDG / AAMR target before import.
  • Reject CHIME_syndrome.yaml as an exact mapping.
  • Preserve normal sialotransferrins, achalasia, alacrima, dysphagia, regurgitation, postural hypotension, hearing impairment, gait disturbance, facial dysmorphism, growth retardation, hypotonia, and intellectual-disability prompts.