2026 ICD-10-CM Diagnosis Code G23.8Other specified degenerative diseases of basal ganglia

ICD-10-CM Codes›G00–G99›G20-G26›G23

ICD-10-CM G23.8
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G23.8 is a billable ICD-10-CM diagnosis code for other specified degenerative diseases of basal ganglia. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other nervous system disorders (often hereditary or degenerative).

Code Identity

ICD-10-CM Code
G23.8
Billable Status
Yes — Valid for Submission
Code Describes
Other specified degenerative diseases of basal ganglia
Short Description
Other specified degenerative diseases of basal ganglia
Same as the full description in the CMS dataset.
Parent Code
G23
Other degenerative diseases of basal ganglia

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG20-G26Extrapyramidal and movement disorders
CategoryG23Other degenerative diseases of basal ganglia
This CodeG23.8Other specified degenerative diseases of basal ganglia

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Aicardi Goutieres syndrome
  • Aicardi Goutieres syndrome type 1
  • Aicardi Goutieres syndrome type 2
  • Aicardi Goutieres syndrome type 3
  • Aicardi Goutieres syndrome type 4
  • Aicardi Goutieres syndrome type 5
  • Atypical pantothenate kinase associated neurodegeneration
  • Autosomal dominant late onset basal ganglia degeneration
  • Basal ganglia degeneration with calcification
  • Calcification of basal ganglia
  • Cerebral degeneration in childhood
  • Childhood-onset basal ganglia degeneration syndrome
  • Chorea due to metabolic disorder
  • Chorea due to neuroferritinopathy
  • Classical pantothenate kinase associated neurodegeneration
  • Dystonia due to familial basal ganglia calcifications
  • Fahr's syndrome
  • Juvenile paralysis agitans of Hunt
  • Neuroferritinopathy
  • Neurological disorder due to excess intake of micronutrients
  • Olivopontocerebellar atrophy with blindness
  • Olivopontocerebellar atrophy with slow eye movement
  • Olivopontocerebellar degeneration
  • Pallidal degeneration
  • Pallidoluysian degeneration
  • Pallidonigrospinal degeneration
  • Parkinsonism with calcification of basal ganglia
  • Pigmentary pallidal degeneration
  • Spondyloenchondromatosis
  • Spondyloenchondromatosis with basal ganglia calcification
  • Sporadic olivopontocerebellar atrophy

Tabular List NotesGuidance

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

Inclusion Terms

  • Calcification of basal ganglia

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

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

    • Atrophy, atrophic(of)
      • Déjérine-Thomas
    • Atrophy, atrophic(of)
      • olivopontocerebellar
    • Calcification
      • basal ganglia
    • Degeneration, degenerative
      • basal nuclei or ganglia
        • specified NEC
    • Degeneration, degenerative
      • olivopontocerebellar (hereditary) (familial)
    • Déjérine-Thomas atrophy
    • Disease, diseased
      • basal ganglia
        • degenerative
          • specified NEC
    • Disease, diseased
      • Fahr (of brain)
    • Fahr disease(of brain)

Clinical ClassificationClinical

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

CCSR NVS006
Other nervous system disorders (often hereditary or degenerative)
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Degenerative Nerve Diseases

Degenerative nerve diseases affect many of your body's activities, such as balance, movement, talking, breathing, and heart function. Many of these diseases are genetic. Sometimes the cause is a medical condition such as alcoholism, a tumor, or a stroke. Other causes may include toxins, chemicals, and viruses.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert G23.8 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
333.0 Degen basal ganglia NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About G23.8Overview

Is G23.8 (Other degenerative diseases of basal ganglia) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other specified degenerative diseases of basal ganglia on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of G23.8?

Under the General Equivalence Mappings, other specified degenerative diseases of basal ganglia converts to ICD-9-CM 333.0 (degen basal ganglia NEC). The mapping is approximate, so confirm the match fits the documentation.

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.