IEMbase 0642: FKTN-related muscular dystrophy-dystroglycanopathy type A
Scope
| Field | Value |
|---|---|
| IEMbase ID | 642 |
| Nosology | 18.2.08.01 |
| Gene | FKTN |
| External IDs | OMIM:253800; ORPHA:272 |
| Generated mapping | UNMAPPED; weak candidate Dystroglycanopathy.yaml |
| Candidate DisMech targets | Dystroglycanopathy.yaml |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents FKTN-CDG type A / Fukuyama congenital muscular dystrophy as an autosomal recessive congenital dystroglycanopathy with brain and eye anomalies.
Biochemical rows include markedly increased plasma creatine kinase, normal serum sialotransferrins, and abnormal matriglycan-specific antibody readout. Clinical and characteristic rows include agyria, pachygyria, cobblestone lissencephaly, Walker-Warburg syndrome, muscle-eye-brain disease, corpus callosum abnormalities, brainstem hypoplasia, cerebellar abnormalities, hydrocephalus, polymicrogyria, psychomotor regression, epilepsy, hypotonia, muscular dystrophy, contractures, calf muscle hypertrophy, dilated cardiomyopathy, respiratory insufficiency from muscle weakness or diaphragm paralysis, scoliosis, cataract, chorioretinal degeneration, optic atrophy, and microphthalmia.
DisMech phenotype coverage
Dystroglycanopathy.yaml includes MDDG4 (FKTN), describing fukutin as the
first ribitol-phosphate transferase and noting documented severity types A4,
B4, and C4. The same file has a type A severity subtype and captures the shared
mechanism, defective alpha-dystroglycan glycosylation, abnormal matriglycan /
laminin binding, elevated CK, muscular dystrophy, cobblestone lissencephaly,
retinal dysplasia, intellectual disability, seizures, hydrocephalus, neonatal
hypotonia, and the severe Walker-Warburg / muscle-eye-brain / Fukuyama
continuum.
Local coverage is less complete for the specific FKTN type A phenotype bundle: contractures, corpus callosum abnormalities, psychomotor regression, polymicrogyria, scoliosis, respiratory insufficiency, calf hypertrophy, and dilated cardiomyopathy are not all represented in the dystroglycanopathy entry as FKTN/type-A-specific phenotype prompts.
Concordance and completeness
Judgement: broad local coverage, not an unmapped disease-family gap.
The generated weak candidate is biologically appropriate but should be promoted from weak candidate to primary broad coverage. The incompleteness is row-level: DisMech models FKTN and type A dystroglycanopathy separately rather than curating the exact FKTN type A/Fukuyama row as its own cross-product entity.
Curation actions
- Map broadly to
Dystroglycanopathy.yaml. - Add exact FKTN type A / Fukuyama cross-product detail only if the project wants row-level MONDO/OMIM coverage.
- Preserve CK, normal sialotransferrins, matriglycan antibody, cortical malformation, eye, cardiac, respiratory, contracture, scoliosis, regression, hypotonia, and muscular dystrophy prompts.