G11.9 Hereditary ataxia, unspecified

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

Applicable to

• Hereditary cerebellar ataxia NOS
• Hereditary cerebellar degeneration
• Hereditary cerebellar disease
• Hereditary cerebellar syndrome

Applies from G11 Hereditary ataxia

Excludes2 (not included here)

• cerebral palsy (G80.-)
• hereditary and idiopathic neuropathy (G60.-)
• metabolic disorders (E70-E88)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 200 — Friedreich and Other Hereditary Ataxias; Huntington Disease
• CMS-HCC V22: HCC 72 — Spinal Cord Disorders/Injuries
• ESRD V24: HCC 72

MS-DRG index

Defines the logic of DRG(s) 058-060 in MDC 01.

Approximate ICD-9-CM (GEMs)

• 334.9 Spinocerebellar disease, unspecified (approximate)

Code annotations containing back-references to G11.9

Back-references to G11

• Type 1 Excludes: R26 Abnormalities of gait and mobility ("hereditary ataxia (G11.-)")
• Type 1 Excludes: R27 Other lack of coordination ("hereditary ataxia (G11.-)")

Diagnosis Index entries for G11.9

• Ataxia, ataxy, ataxic › brain (hereditary)
• Ataxia, ataxy, ataxic › cerebellar (hereditary)
• Ataxia, ataxy, ataxic › cerebral (hereditary)
• Ataxia, ataxy, ataxic › hereditary
• Degeneration, degenerative › cerebellar NOS › primary (hereditary) (sporadic)
• Disease, diseased › spinocerebellar (hereditary)
• Paralysis, paralytic (complete) (incomplete) › ataxic (hereditary)
• Sclerosis, sclerotic › hereditary › cerebellar
• Syndrome › cerebellar › hereditary

Nearby codes

• G11.3 Cerebellar ataxia with defective DNA repair
• G11.4 Hereditary spastic paraplegia
• G11.5 Hypomyelination - hypogonadotropic hypogonadism - hypodontia
• G11.6 Leukodystrophy with vanishing white matter disease
• G11.8 Other hereditary ataxias
• G11.9 Hereditary ataxia, unspecified (this code)