ICD-10 Code G23.9 – Degenerative disease of basal ganglia, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G23.9 – Degenerative disease of basal ganglia, unspecified
What it is
This code identifies a degenerative disorder affecting the basal ganglia, but the exact type is not specified in the record. Use it when documentation confirms a basal ganglia degeneration without naming a more precise diagnosis.
Clinical signs
Clinical features vary; refer to documentation. Commonly, these disorders involve movement abnormalities such as rigidity, bradykinesia, tremor, dystonia, or gait disturbance.
When to use this code
Use G23.9 when the provider documents degenerative disease of the basal ganglia and does not identify a specific subtype. It also fits when the note confirms a degenerative basal ganglia process but the available record is incomplete. If a more specific disorder is named, code that diagnosis instead.
Do not use for
Do not use this code for Parkinson disease, Huntington disease, or other specifically documented movement disorders. Check documentation if the record describes another neurologic condition or a nondegenerative cause.
Coding tip
Code the most specific documented basal ganglia disorder first; use G23.9 only when the provider leaves the condition unspecified.