Other degenerative diseases of basal ganglia (G23) ICD-10-CM
The G23 code range covers other degenerative diseases of basal ganglia with 7 ICD-10-CM diagnosis codes. 6 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
- multi-system degeneration of the autonomic nervous system G90.3
Codes in the G23 Range 7 codes · 6 billable
- G23 Other degenerative diseases of basal gangliaNon-billable
- G23.0 Hallervorden-Spatz disease
- G23.1 Progressive supranuclear ophthalmoplegia [Steele-Richardson-Olszewski]
- G23.2 Striatonigral degeneration
- G23.3 Hypomyelination with atrophy of the basal ganglia and cerebellum
- G23.8 Other specified degenerative diseases of basal ganglia
- G23.9 Degenerative disease of basal ganglia, unspecified
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the G23 range.
Machado-Joseph Disease
A dominantly-inherited ATAXIA first described in people of Azorean and Portuguese descent, and subsequently identified in Brazil, Japan, China, and Australia. This disorder is classified as one of the SPINOCEREBELLAR ATAXIAS (Type 3) and has been associated with a mutation of the MJD1 gene on chromosome 14. Clinical features include progressive ataxia, DYSARTHRIA, postural instability, nystagmus, eyelid retraction, and facial FASCICULATIONS. DYSTONIA is prominent in younger patients (referred to as Type I Machado-Joseph Disease). Type II features ataxia and ocular signs; Type III features MUSCULAR ATROPHY and a sensorimotor neuropathy; and Type IV features extrapyramidal signs combined with a sensorimotor neuropathy. (From Clin Neurosci 1995;3(1):17-22; Ann Neurol 1998 Mar;43(3):288-96)
Striatonigral Degeneration
A sporadic neurodegenerative disease with onset in middle-age characterized clinically by Parkinsonian features (e.g., MUSCLE RIGIDITY; HYPOKINESIA; stooped posture) and HYPOTENSION. This condition is considered a clinical variant of MULTIPLE SYSTEM ATROPHY. Pathologic features include a prominent loss of neurons in the zona compacta of the SUBSTANTIA NIGRA and PUTAMEN. (From Adams et al., Principles of Neurology, 6th ed, p1075-6)
About the G23 Code Range
The ICD-10 code section G23 is used to classify other degenerative diseases of the basal ganglia, a group of brain disorders affecting movement and coordination. These codes help specify distinct conditions such as Hallervorden-Spatz disease (G23.0), Progressive supranuclear ophthalmoplegia (G23.1), and other related neurodegenerative disorders involving the basal ganglia.
This section includes codes for various hereditary and sporadic basal ganglia disorders. For example, G23.0 covers Hallervorden-Spatz disease, also known by synonyms like "dementia due to genetic disease" and "chorea due to classical pantothenate kinase associated neurodegeneration." Meanwhile, G23.1 describes progressive supranuclear ophthalmoplegia, recognized by terms such as "progressive supranuclear palsy" and "supranuclear gaze palsy." The code G23.8 refers to other specified degenerative basal ganglia diseases, including Fahr's syndrome and neuroferritinopathy, with many synonyms capturing different presentations of basal ganglia calcification and degeneration. Lastly, G23.9 denotes unspecified degenerative disease of the basal ganglia, linked to terms like "pallidal degeneration." These ICD-10 codes assist healthcare professionals in accurately diagnosing and documenting specific basal ganglia degenerative disorders.
Questions About This Page
How many billable codes are in the G23 range?
Of the 7 codes in this range, 6 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the G23 range classify?
The range classifies other degenerative diseases of basal ganglia. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
