2026 ICD-10-CM Diagnosis Code G40.C09Lafora progressive myoclonus epilepsy, not intractable, without status epilepticus

ICD-10-CM Codes›G00–G99›G40-G47›G40

ICD-10-CM G40.C09
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G40.C09 is a billable ICD-10-CM diagnosis code for lafora progressive myoclonus epilepsy, not intractable, without status epilepticus. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 100 through 101. Coders also document this condition as lafora disease. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Epilepsy; convulsions.

Code Identity

ICD-10-CM Code
G40.C09
Billable Status
Yes — Valid for Submission
Code Describes
Lafora progressive myoclonus epilepsy, not intractable, without status epilepticus
Short Description
Lafora progr myoclonus epilepsy, not ntrct, without stat epi
Parent Code
G40.C0
Lafora progressive myoclonus epilepsy, not intractable

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG40-G47Episodic and paroxysmal disorders
CategoryG40Epilepsy and recurrent seizures
This CodeG40.C09Lafora progressive myoclonus epilepsy, not intractable, without status epilepticus

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Lafora disease

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Lafora progressive myoclonus epilepsy NOS

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

  • - Lafora disease - See Also: Epilepsy, progressive, Lafora; - G40.C09

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Disease, diseased
      • Lafora body
    • Epilepsy, epileptic, epilepsia(attack) (cerebral) (convulsion) (fit) (seizure)
      • Lafora progressive myoclonus
    • Epilepsy, epileptic, epilepsia(attack) (cerebral) (convulsion) (fit) (seizure)
      • myoclonus, myoclonic
        • progressive
          • Lafora
    • Epilepsy, epileptic, epilepsia(attack) (cerebral) (convulsion) (fit) (seizure)
      • myoclonus, myoclonic
        • progressive
          • Lafora
            • not intractable
    • Epilepsy, epileptic, epilepsia(attack) (cerebral) (convulsion) (fit) (seizure)
      • myoclonus, myoclonic
        • progressive
          • Lafora
            • not intractable
              • without status epilepticus
    • Epilepsy, epileptic, epilepsia(attack) (cerebral) (convulsion) (fit) (seizure)
      • progressive (familial) myoclonic
        • Lafora
    • Lafora disease

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NVS009
Epilepsy; convulsions
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Lafora Disease

    a form of stimulus sensitive myoclonic epilepsy inherited as an autosomal recessive condition. the most common presenting feature is a single seizure in the second decade of life. this is followed by progressive myoclonus, myoclonic seizures, tonic-clonic seizures, focal occipital seizures, intellectual decline, and severe motor and coordination impairments. most affected individuals do not live past the age of 25 years. concentric amyloid (lafora) bodies are found in neurons, liver, skin, bone, and muscle (from menkes, textbook of childhood neurology, 5th ed, pp111-110).

  • EPM2A wt Allele|EPM2|EPM2A Glucan Phosphatase, Laforin wt Allele|EPM2A, Laforin Glucan Phosphatase Gene|Epilepsy, Progressive Myoclonus Type 2, Lafora Disease (Laforin) Gene|LD|LDE|MELF|MELF2

    human epm2a wild-type allele is located in the vicinity of 6q24.3 and is approximately 353 kb in length. this allele, which encodes laforin, plays a role in protein phosphatase activity and glycogen metabolism. loss of function mutations in the gene are associated with myoclonic epilepsy of lafora 1.

  • Lafora Disease

    a rare, fatal autosomal recessive inherited disorder caused by mutations in the genes epm2a and epm2b. it is characterized by the presence of cytoplasmic inclusion bodies called lafora bodies in many cells of the body including neurons, muscle cells, and liver cells. the lafora bodies contain mucopolysaccharides. signs and symptoms include seizures, myoclonus, ataxia, and dementia.

Code History & ChangesHistory

Replacement G40.C09 replaces the following previously assigned code(s):

  • G40.309 - Gen idiopathic epilepsy, not intractable, w/o stat epi
FY 2024AddedAdded to the ICD-10-CM code setEffective October 1, 2023.
FY 2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About G40.C09Overview

Is G40.C09 (Lafora progressive myoclonus epilepsy, not intractable) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report lafora progressive myoclonus epilepsy, not intractable, without status epilepticus on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does G40.C09 group to?

When lafora progressive myoclonus epilepsy, not intractable, without status epilepticus is the principal diagnosis on an inpatient stay, it groups to MS-DRG 100, 101, with relative weights from 0.9026 to 1.9368 depending on complications. Higher weights mean higher Medicare reimbursement.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.