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IEMbase 0608: STT3A-related congenital disorder of glycosylation

Scope

Field Value
IEMbase ID 608
Nosology 18.1.17.01
Gene STT3A
External IDs OMIM:615596; OMIM:601134; ORPHA:370921
Generated mapping CANDIDATE; ALG12_Congenital_Disorder_of_Glycosylation.yaml
Candidate DisMech targets None exact
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents STT3A-related congenital disorder of glycosylation, labelled STT3A-CDG. The record is autosomal recessive, classified under N-glycosylation disorders, has unknown treatability, and has no treatment rows.

Biochemical rows include increased serum N-glycans, normal-to-increased asialotransferrin and disialotransferrin, decreased-to-normal tetrasialotransferrin, and decreased-to-normal factor VIII and von Willebrand factor. Clinical rows include developmental delay, intellectual disability, seizures, hypotonia, gastrointestinal dysmotility, failure to thrive, microcephaly, and cerebellar atrophy on MRI.

DisMech phenotype coverage

ALG12_Congenital_Disorder_of_Glycosylation.yaml is a false-positive CDG-class candidate. It models ALG12 mannosyltransferase deficiency, not STT3A, the catalytic subunit of the oligosaccharyltransferase complex responsible for co-translational N-glycosylation. Although both records share type I CDG features, neurodevelopmental involvement, and coagulation-related clues, the gene, enzymatic step, and disease identity differ.

No exact STT3A-CDG target was identified locally.

Concordance and completeness

Judgement: true local gap; reject ALG12-CDG as exact coverage.

The generated candidate is useful only as neighboring CDG biology. IEMbase 0608 needs a distinct STT3A/oligosaccharyltransferase CDG target before any phenotype import.

Curation actions

  • Create or identify an exact STT3A-CDG target before import.
  • Reject ALG12_Congenital_Disorder_of_Glycosylation.yaml as an exact mapping.
  • Preserve N-glycan and transferrin isoform readouts, factor VIII, von Willebrand factor, seizures, hypotonia, developmental delay, intellectual disability, gastrointestinal dysmotility, failure to thrive, microcephaly, and cerebellar-atrophy prompts.