IEMbase 0338: B4GALT1-related beta-1,4-galactosyltransferase 1 deficiency
Scope
| Field | Value |
|---|---|
| IEMbase ID | 338 |
| Nosology | 18.1.29.01 |
| Gene | B4GALT1 |
| External IDs | OMIM:607091; ORPHA:79332 |
| Generated mapping | UNMAPPED; low-score candidate GM1_Gangliosidosis_Type_1.yaml |
| Candidate DisMech targets | Reject GM1_Gangliosidosis_Type_1.yaml |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents B4GALT1-CDG/CDG-IId, a type II congenital disorder of glycosylation. Characteristic rows include axial hypotonia, facial dysmorphism, and myopia. Additional clinical rows include recurrent diarrhea, hypertelorism, long philtrum, low-set ears, perinatal bleeding diathesis, prominent forehead, and thin upper lip.
The biochemical rows include increased ASAT, cholinesterase, and creatine kinase; asialotransferrin, disialotransferrin, monosialotransferrin, trisialotransferrin, tetrasialotransferrin, hypogalactosylated transferrin glycans, and type II sialotransferrins; fibrinogen/APTT; and antithrombin III and factor XI. No treatment rows are present.
DisMech phenotype coverage
The generated GM1 gangliosidosis candidate is a lexical false positive around "beta-galactosyl" wording. GM1 gangliosidosis type 1 is a GLB1 lysosomal beta-galactosidase storage disorder with GM1 ganglioside accumulation, neurodegeneration, hepatosplenomegaly, dysostosis multiplex, coarse facies, and cherry-red macula. It is not B4GALT1-CDG and does not model a Golgi galactosyltransferase defect.
No standalone B4GALT1-CDG entry exists locally. The CDG module and grouping provide only family-level context.
Concordance and completeness
Judgement: true local disease gap; reject the GM1 candidate.
The IEMbase record is a type II glycosylation-processing disorder with hypogalactosylated transferrin and coagulation-protein signals. That is mechanistically distinct from lysosomal beta-galactosidase deficiency and GM1 ganglioside storage.
Curation actions
- Add a standalone B4GALT1-CDG target before treating this IEMbase record as mapped.
- Do not map to GM1 gangliosidosis based on the shared galactose-related wording.
- Preserve hypogalactosylated transferrin, type II glycan fractions, bleeding/coagulation, diarrhea, myopia, dysmorphism, and CK/transaminase rows as future-curation prompts.