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IEMbase 0284: GLB1-related Beta-galactosidase-1 deficiency, GM1 gangliosidosis

Scope

Field Value
IEMbase ID 284
Nosology 20.1.14.01
Gene GLB1
External IDs OMIM:253010; ORPHA:79255
Generated mapping UNMAPPED; weak candidate GM1_Gangliosidosis_Type_1.yaml
Candidate DisMech targets GM1_Gangliosidosis_Type_1.yaml; GM1_Gangliosidosis_Type_2.yaml; GM1_Gangliosidosis_Type_3.yaml
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents GLB1-related beta-galactosidase-1 deficiency as a broad GM1 gangliosidosis record rather than a single age-defined type. Inheritance is autosomal recessive, treatability is unknown, and prevalence is listed as 1:100,000 to 1:200,000.

The clinical rows span infantile through adult disease: Alder-Reilly anomaly, ascites, brain atrophy, cardiomyopathy, corneal clouding, dystonia, edema, foam cells, gait disturbance, gingival hypertrophy, intellectual disability, macroglossia, seizures, and speech disturbance. The biochemical rows list increased urinary oligosaccharides, increased mucopolysaccharide/unsaturated keratan sulfate ratio, and increased serum LysoGM1.

DisMech phenotype coverage

DisMech has separate local entries for GM1_Gangliosidosis_Type_1.yaml, GM1_Gangliosidosis_Type_2.yaml, and GM1_Gangliosidosis_Type_3.yaml. Together they cover the GLB1 beta-galactosidase deficiency spectrum better than any single file.

Type 1 captures infantile GLB1 disease with neurodegeneration, developmental regression, hepatosplenomegaly, dysostosis multiplex, coarse facial features, and cherry-red macula. Type 2 captures intermediate disease with decreased beta-galactosidase activity, developmental regression, seizures, ataxia, feeding difficulty/dysphagia, speech decline/dysarthria, kyphosis, corneal clouding, cardiomyopathy, cerebral atrophy, muscle weakness, and strabismus. Type 3 captures adult/chronic basal-ganglia-predominant disease with dystonia, parkinsonism, dysarthria, and gait disturbance. The local entries also include gene therapy and supportive-care framing, but do not appear to model the IEMbase LysoGM1 row or the urinary oligosaccharide row as biochemical entries.

Concordance and completeness

Judgement: generated UNMAPPED is a false negative, but the best local target is the GLB1 GM1 gangliosidosis spectrum, not only GM1_Gangliosidosis_Type_1.yaml.

IEMbase and DisMech agree on GLB1 identity, autosomal recessive inheritance, beta-galactosidase deficiency, neurologic regression/intellectual disability, seizures, brain atrophy, corneal clouding, cardiomyopathy, dystonia, gait disturbance, and speech disturbance. DisMech is more nuanced for age-defined subtypes and mechanistic interpretation. IEMbase is broader in one record and adds laboratory prompts: urinary oligosaccharides, LysoGM1, and mucopolysaccharide/keratan-sulfate ratio.

IEMbase also adds Alder-Reilly anomaly, foam cells, gingival hypertrophy, macroglossia, edema, and ascites as review prompts. Some of these may be type-specific or nonspecific lysosomal-storage features, so they should be imported only with disease- and type-specific support.

Curation actions

  • Resolve this record to the local GM1 gangliosidosis spectrum: GM1_Gangliosidosis_Type_1.yaml, GM1_Gangliosidosis_Type_2.yaml, and GM1_Gangliosidosis_Type_3.yaml.
  • Treat GM1_Gangliosidosis_Type_1.yaml alone as too narrow for this IEMbase record.
  • Review LysoGM1, urinary oligosaccharides, Alder-Reilly anomaly, foam cells, gingival hypertrophy, macroglossia, edema, and ascites for possible subtype enrichment.