IEMbase 0260: MAN2B1-related Alpha-mannosidase B deficiency
Scope
| Field | Value |
|---|---|
| IEMbase ID | 260 |
| Nosology | 20.3.03.01 |
| Gene | MAN2B1 |
| External IDs | OMIM:248500; ORPHA:309288 |
| Generated mapping | MAPPED; Alpha_Mannosidosis.yaml |
| Candidate DisMech targets | Alpha_Mannosidosis.yaml |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents this as MAN2B1-related alpha-mannosidase B deficiency, with alternate labels alpha-mannosidosis and LAMAN. The record is autosomal recessive and treatability is marked yes.
The treatment section lists velmanase alfa enzyme replacement therapy with level 1c evidence and PMID 29716835, plus bone marrow transplantation with level 4 evidence and PMID 29772816. Biochemical rows include decreased alpha-mannosidase B activity in fibroblasts and white blood cells, plus increased urinary mannose-oligosaccharides. Clinical rows include psychotic behavior, corneal clouding and deposits, dental spacing, foam cells, hepatomegaly, hernias, immunodeficiency, intellectual disability, macroglossia, prognathism, short stature, spasticity, and vacuolated lymphocytes.
DisMech phenotype coverage
Alpha_Mannosidosis.yaml is the correct local target. The local entry covers
biallelic MAN2B1 pathogenic variants, deficient lysosomal alpha-mannosidase
activity, impaired degradation of mannose-rich oligosaccharides, immune
deficiency, recurrent infections, hearing impairment, intellectual disability,
coarse facial features, skeletal dysplasia, hepatosplenomegaly, ocular
findings, reduced enzyme activity, increased urinary mannose-rich
oligosaccharides, velmanase alfa, hematopoietic stem cell transplantation,
supportive care, and genetic counseling.
Concordance and completeness
Judgement: correct mapping with high concordance.
IEMbase and DisMech agree on MAN2B1/alpha-mannosidosis identity, autosomal recessive inheritance, reduced alpha-mannosidase activity, urinary mannose-oligosaccharide elevation, immune deficiency, intellectual disability, ocular/corneal findings, hepatomegaly, facial/oral findings, short stature, spasticity, velmanase alfa, and transplant. IEMbase adds compact prompts for foam cells, vacuolated lymphocytes, dental spacing, psychotic behavior, and corneal deposits.
Curation actions
- Keep this record mapped to
Alpha_Mannosidosis.yaml. - No mapping correction is needed.
- Use IEMbase's cellular, dental, psychiatric, and corneal-deposit rows as enrichment prompts for future alpha-mannosidosis review.