ICD-10 Code G40.C – Lafora progressive myoclonus epilepsy (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G40.C – Lafora progressive myoclonus epilepsy
What it is
G40.C identifies Lafora progressive myoclonus epilepsy, a rare inherited epilepsy syndrome with progressive neurologic decline. Use it when documentation specifically names Lafora disease or Lafora progressive myoclonus epilepsy.
Clinical signs
Typical findings include myoclonic seizures, generalized seizures, and worsening neurologic function over time. Clinical features vary; refer to documentation for the confirmed diagnosis and any associated cognitive decline.
When to use this code
Use G40.C when the clinician documents Lafora progressive myoclonus epilepsy as the confirmed diagnosis. It fits encounters for established disease, evaluation of seizure disorder with documented Lafora syndrome, or follow-up of known cases. Check documentation if the note only says epilepsy or myoclonus without the Lafora subtype.
Do not use for
Do not use this code for unspecified epilepsy, isolated myoclonus, or other progressive myoclonic epilepsies that are not documented as Lafora disease. Check documentation when the subtype is unclear.
Coding tip
Code the specific Lafora diagnosis only when the record states it clearly; otherwise, choose the documented epilepsy code and query if needed.