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IEMbase 0609: STT3B-related congenital disorder of glycosylation

Scope

Field Value
IEMbase ID 609
Nosology 18.1.27.01
Gene STT3B
External IDs OMIM:615597; ORPHA:370924
Generated mapping CANDIDATE; ALG12_Congenital_Disorder_of_Glycosylation.yaml
Candidate DisMech targets None exact
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents STT3B-CDG as an autosomal recessive N-glycosylation disorder with unknown treatability and no treatment rows. Biochemical rows show a type I transferrin pattern: increased serum asialotransferrin and disialotransferrin, with decreased serum tetrasialotransferrin in the neonatal period.

Clinical rows emphasize neonatal-onset multisystem disease: developmental delay, hypotonia, failure to thrive, gastrointestinal dysmotility, hepatopathy, respiratory failure, seizures, microcephaly, cerebral atrophy on MRI, optic atrophy, thrombocytopenia, intellectual disability, undescended testes, hypoplastic scrotum, and broader external-genital abnormality.

DisMech phenotype coverage

ALG12_Congenital_Disorder_of_Glycosylation.yaml is a false-positive CDG-class candidate. ALG12-CDG is an ER lipid-linked oligosaccharide assembly disorder caused by ALG12 mannosyltransferase deficiency, whereas STT3B encodes an oligosaccharyltransferase catalytic subunit involved in N-glycan transfer.

No exact STT3B-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 N-glycosylation biology. IEMbase 0609 needs a distinct STT3B/oligosaccharyltransferase CDG target before phenotype import.

Curation actions

  • Create or identify an exact STT3B-CDG target before import.
  • Reject ALG12_Congenital_Disorder_of_Glycosylation.yaml as an exact mapping.
  • Preserve transferrin type I pattern, neonatal respiratory/hepatic/coagulation, neurodevelopmental, optic-atrophy, and genital-phenotype prompts.