IEMbase 0556: GNPTAB-related mucolipidosis III alpha/beta
Scope
| Field | Value |
|---|---|
| IEMbase ID | 556 |
| Nosology | 20.6.01.04 |
| Gene | GNPTAB |
| External IDs | OMIM:252600; ORPHA:577 |
| Generated mapping | MAPPED; Mucolipidosis_Type_III_Alpha_Beta.yaml |
| Candidate DisMech targets | Mucolipidosis_Type_III_Alpha_Beta.yaml |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents GNPTAB-related UDP-N-acetylglucosamine-1-phosphotransferase subunit alpha/beta deficiency, labeled as mucolipidosis III alpha-beta and pseudo-Hurler polydystrophy. The record is autosomal recessive, and treatability is unknown. No treatment rows are listed.
The biochemical rows include decreased fibroblast/RBC enzyme activity, increased serum enzyme activity, and normal-to-increased urinary glycosaminoglycans and oligosaccharides. Characteristic clinical rows include coarse facial features, corneal clouding, hernias, hip dislocation, joint contractures, and osteodystrophy. Additional rows include aortic insufficiency, extensive dermal melanocytosis, foam cells, gingival hypertrophy, intellectual disability, macroglossia, and psychomotor retardation.
DisMech phenotype coverage
Mucolipidosis_Type_III_Alpha_Beta.yaml is the correct local target. The local
entry models autosomal recessive GNPTAB disease, reduced alpha/beta
GlcNAc-1-phosphotransferase activity, impaired mannose-6-phosphate lysosomal
hydrolase targeting, extracellular lysosomal enzyme leakage, intracellular
storage of incompletely degraded glycosaminoglycans and sphingolipids, and an
attenuated childhood-onset course compared with mucolipidosis II.
Local phenotypes include growth slowing, joint stiffness and pain, dysostosis multiplex, osteoporosis and osteoarthritis, facial coarsening, conductive hearing impairment or otitis, cardiac valve disease, gait disturbance, and mild intellectual disability.
Concordance and completeness
Judgement: correct high-concordance mapping to
Mucolipidosis_Type_III_Alpha_Beta.yaml.
IEMbase and DisMech agree on GNPTAB identity, recessive inheritance, ML III alpha/beta scope, phosphotransferase deficiency, lysosomal hydrolase mistargeting, serum-versus-cell enzyme directionality, joint and skeletal disease, coarse features, corneal clouding, intellectual/psychomotor involvement, and cardiac valve involvement. DisMech is stronger for the attenuated progression and lysosomal-targeting mechanism.
IEMbase adds useful prompts for hernias, hip dislocation, extensive dermal melanocytosis, foam cells, gingival hypertrophy, macroglossia, urinary GAGs and oligosaccharides, and aortic insufficiency.
Curation actions
- Keep this record mapped to
Mucolipidosis_Type_III_Alpha_Beta.yaml. - Consider adding IEMbase compartment-specific enzyme-assay directionality, urinary GAG/oligosaccharide rows, hernia, hip, dermal melanocytosis, foam cell, macroglossia, and aortic-insufficiency prompts after evidence review.
- Keep this distinct from GNPTAB-related mucolipidosis II and from GNPTG-related mucolipidosis III gamma.