IEMbase 0646: FKRP-related muscular dystrophy-dystroglycanopathy type B
Scope
| Field | Value |
|---|---|
| IEMbase ID | 646 |
| Nosology | 18.2.09.03 |
| Gene | FKRP |
| External IDs | OMIM:606612; ORPHA:34515 |
| Generated mapping | UNMAPPED; weak candidate Dystroglycanopathy.yaml |
| Candidate DisMech targets | Dystroglycanopathy.yaml |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents FKRP-CDG type B as autosomal recessive congenital muscular dystrophy-dystroglycanopathy with or without intellectual disability.
Biochemical rows include markedly increased plasma creatine kinase and normal serum sialotransferrins across ages. Clinical rows include muscular dystrophy and hypotonia as characteristic features, with optional cerebellar abnormalities, cerebellar white-matter MRI abnormalities, feeding difficulties, intellectual disability, microcephaly, nodular heterotopia, pachygyria, and spinal abnormalities.
DisMech phenotype coverage
Dystroglycanopathy.yaml includes the FKRP gene subtype and the type B severity
subtype. It covers the shared matriglycan defect, muscular dystrophy, elevated
CK, hypotonia, variable intellectual disability, and the principle that
structural brain abnormalities may occur in type B but are less severe than in
type A.
The local entry does not spell out the FKRP type B phenotype bundle: nodular heterotopia, cerebellar white-matter abnormalities, feeding difficulties, microcephaly, and spinal abnormalities are not captured as FKRP B5-specific phenotype prompts.
Concordance and completeness
Judgement: broad local coverage with row-level incompleteness.
DisMech covers FKRP and type B dystroglycanopathy, so this is not a true absence of local coverage. The missing piece is an exact FKRP type B / congenital-with-or-without-ID subtype that preserves the milder brain and feeding/spinal phenotype spectrum.
Curation actions
- Map broadly to
Dystroglycanopathy.yaml. - Consider adding FKRP type B / MDDG B5 detail under the FKRP subtype if exact IEMbase row coverage is prioritized.
- Preserve CK, normal sialotransferrins, hypotonia, muscular dystrophy, variable ID, cerebellar/white-matter, nodular heterotopia, pachygyria, feeding, microcephaly, and spinal prompts.