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IEMbase 0382: CLN8-related Northern epilepsy variant

Scope

Field Value
IEMbase ID 382
Nosology 20.4.07.02
Gene CLN8
External IDs OMIM:610003; ORPHA:228354
Generated mapping UNMAPPED; no candidate
Candidate DisMech targets Broad Neuronal_Ceroid_Lipofuscinosis.yaml context only
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents autosomal recessive CLN8-related Northern epilepsy variant, also listed as CLN8 disease, progressive epilepsy with mental retardation, and CLN8-EPMR.

Clinical rows emphasize seizures, including complex partial and tonic-clonic seizures, plus behavioral disorder, cognitive decline, movement disorder, ataxia, EEG abnormalities, storage material on electron microscopy, cerebral and cerebellar atrophy on MRI, myoclonus, neurodegeneration, and speech abnormality. There are no biochemical or treatment rows.

DisMech phenotype coverage

There is broad local neuronal ceroid lipofuscinosis context, and Neuronal_Ceroid_Lipofuscinosis.yaml includes CLN8 as a causative gene for the NCL umbrella. However, the current local file does not provide a standalone Northern epilepsy/CLN8-EPMR disease target or a leaf entry that captures this specific CLN8 phenotype.

This conclusion is consistent with the earlier CLN8 late-infantile comparison: the broad NCL file is useful shared context, but it should not be treated as an exact replacement for missing CLN8 leaf diseases. Adult neuronal ceroid lipofuscinosis/Kufs disease entries are also not valid targets for this Northern epilepsy variant.

Concordance and completeness

Judgement: true subtype/leaf gap; keep unmapped at disease level.

The local NCL umbrella supports the shared CLN8/NCL biology but lacks the CLN8-EPMR-specific seizure, cognitive, movement, EEG, storage-material, and MRI phenotype frame represented by IEMbase.

Curation actions

  • Keep this record unmapped until a CLN8 Northern epilepsy/CLN8-EPMR target or explicit subtype anchor exists.
  • Use Neuronal_Ceroid_Lipofuscinosis.yaml only as broad NCL context.
  • Do not map this record to adult NCL/Kufs entries or to the separate late-infantile CLN8 record without an explicit subtype decision.