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IEMbase 0633: VPS13B-related Cohen syndrome

Scope

Field Value
IEMbase ID 633
Nosology 19.5.11.01
Gene VPS13B
External IDs OMIM:216550; ORPHA:193
Generated mapping UNMAPPED
Candidate DisMech targets None exact; GM3_Synthase_Deficiency.yaml is a false candidate
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents VPS13B-related Pepper syndrome / Cohen syndrome / VPS13B-CDG as an autosomal recessive disorder with unknown treatability and no treatment rows.

Biochemical rows include increased serum agalactosotransferrin and asialotransferrin in adolescence/adulthood with normal serum transferrin. Clinical and characteristic rows include intellectual disability, myopia, optional neutropenia, chorioretinal degeneration, joint laxity, microcephaly, and obesity.

DisMech phenotype coverage

No exact VPS13B/Cohen syndrome entry was identified. GM3_Synthase_Deficiency.yaml is a false candidate driven by overlapping neurodevelopmental and retinal features; GM3 synthase deficiency is ST3GAL5-related ganglioside biosynthesis disease, not VPS13B/Cohen syndrome.

Concordance and completeness

Judgement: true local gap.

The G2P triage table also identifies VPS13B-related Cohen syndrome as lacking a DisMech disease anchor, which is consistent with the generated unmapped result.

Curation actions

  • Do not map to GM3 synthase deficiency.
  • Curate VPS13B/Cohen syndrome as a separate disorder if selected.
  • Preserve transferrin glycoform rows, myopia, chorioretinal degeneration, neutropenia, intellectual disability, microcephaly, obesity, and joint-laxity prompts.