ICD-10-CM 2027 diagnosis code

G23Other degenerative diseases of basal ganglia

Not billable — use a more specific code

G23 is a header code, so it can't be reported by itself. Choose one of the 6 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About G23

G23 is the ICD-10-CM diagnosis code for other degenerative diseases of basal ganglia. It belongs to block G20-G26 (extrapyramidal and movement disorders) and chapter 6 (diseases of the nervous system). It is a header code, so it can't be reported by itself; one of its 6 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: G23.0 (disease), G23.1 ([Steele-Richardson-Olszewski]), G23.2 (degeneration), G23.3 (cerebellum), G23.8 (ganglia) and G23.9 (unspecified).

The conditions in its Excludes2 note aren't part of G23, but may be coded alongside it if the patient has both: multi-system degeneration of the autonomic nervous system (G90.3).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under G23

Coding notes

Excludes2Not included here — may be reported together if both conditions exist

multi-system degeneration of the autonomic nervous system (G90.3)

Notes that apply from higher levels

Instructions written at a parent level also apply to G23.

Broader instructions also apply from Chapter 6: Diseases of the nervous system.

Code history

2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027

FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
No changes since FY2016.

Common questions about G23

Is G23 billable?: No. G23 is a header code. Report one of its more specific subcodes instead.