G23.3 Hypomyelination with atrophy of the basal ganglia and cerebellum

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applicable to

• H-ABC
• TUBB4A-related neurologic disorders

Applies from G23 Other degenerative diseases of basal ganglia

Excludes2 (not included here)

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

Risk adjustment (HCC)

• CMS-HCC V28: HCC 199 — Parkinson and Other Degenerative Disease of Basal Ganglia
• CMS-HCC V22: HCC 78 — Parkinson's and Huntington's Diseases
• RxHCC V08: HCC 161 — Parkinson Disease
• ESRD V24: HCC 78

MS-DRG index

Defines the logic of DRG(s) 056-057 in MDC 01.

Code annotations containing back-references to G23.3

Back-references to G23

• Type 2 Excludes: F98.4 Stereotyped movement disorders ("movement disorders of organic origin (G20-G25)")
• Type 1 Excludes: R25 Abnormal involuntary movements ("specific movement disorders (G20-G26)")

Diagnosis Index entries for G23.3

• Disorder (of) › neurological NEC › TUBB4A-related
• H-ABC (hypomyelination with atrophy of the basal ganglia and cerebellum)
• Hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC)

Nearby codes

• G23 Other degenerative diseases of basal ganglia
• 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 (this code)
• G23.8 Other specified degenerative diseases of basal ganglia
• G23.9 Degenerative disease of basal ganglia, unspecified