G40.C01
BillableLafora progressive myoclonus epilepsy, not intractable, with status epilepticus
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G40.C01 an HCC code?
Yes. G40.C01 maps to Seizure Disorders and Convulsions under the CMS-HCC V28 risk adjustment model (and Seizure Disorders and Convulsions under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for G40.C01
For G40.C01 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed G40.C01 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
G40.C01 is the ICD-10-CM diagnosis code for lafora progressive myoclonus epilepsy, not intractable, with status epilepticus. Lafora disease is a rare, inherited progressive epilepsy that causes myoclonic seizures and progressive neurological decline, typically beginning in childhood. This code indicates the condition is medication-responsive but the patient is currently experiencing status epilepticus. G40.C01 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering episodic and paroxysmal disorders (g40-g47).
Under the CMS-HCC V28 risk adjustment model, G40.C01 maps to Seizure Disorders and Convulsions (HCC 201) with a community, non-dual, aged base RAF weight of 0.262. Under the older V24 model, G40.C01 mapped to the same category but with a base RAF weight of 0.244 — V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Lafora disease is a progressive myoclonus epilepsy; ensure genetic or pathological confirmation is documented. Because G40.C01 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for G40.C01 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Lafora disease is a progressive myoclonus epilepsy; ensure genetic or pathological confirmation is documented
- •Document presence of status epilepticus and that the condition is not intractable (responds to treatment)
Clinical Significance
Lafora progressive myoclonus epilepsy with status epilepticus is a rare, fatal autosomal recessive disorder caused by mutations in the EPM2A or NHLRC1 genes. Lafora disease causes progressive neurological decline with myoclonic seizures, cognitive deterioration, and visual hallucinations. Status epilepticus in Lafora disease is a medical emergency that may be particularly difficult to manage given the progressive nature of the disease.
Documentation Requirements
- ✓Confirmed Lafora disease diagnosis (genetic testing or skin biopsy showing Lafora bodies)
- ✓Active status epilepticus during the encounter
- ✓Statement that seizures currently respond to medication
- ✓Emergency interventions for status epilepticus
- ✓Current medication regimen
- ✓Documentation of disease progression stage
Commonly Confused Codes
- •G40.C09 — Lafora disease, not intractable, WITHOUT status epilepticus
- •G40.C11 — Lafora disease, INTRACTABLE, with status epilepticus
- •G40.B01 — Juvenile myoclonic epilepsy with status epilepticus; JME is NOT progressive
- •G40.401 — Other generalized epilepsy with status epilepticus; less specific
- •G40.833 — Dravet syndrome, intractable, with status epilepticus; different genetic epilepsy