2027 ICD-10-CM Diagnosis Code G80.4Ataxic cerebral palsy

ICD-10-CM Codes›G00–G99›G80-G83›G80

ICD-10-CM G80.4
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

G80.4 is a billable ICD-10-CM diagnosis code for ataxic cerebral palsy. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 91 through 93. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cerebral palsy.

For Medicare Advantage risk adjustment, G80.4 maps to CMS-HCC Category 192 (Cerebral Palsy, Except Quadriplegic) under the V28 model, adding a risk factor of about 0.314 for a community, non-dual, aged beneficiary in payment year 2027.

Code Identity

ICD-10-CM Code
G80.4
Billable Status
Yes — Valid for Submission
Code Describes
Ataxic cerebral palsy
Short Description
Ataxic cerebral palsy
Same as the full description in the CMS dataset.
Parent Code
G80
Cerebral palsy

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG80-G83Cerebral palsy and other paralytic syndromes
CategoryG80Cerebral palsy
This CodeG80.4Ataxic cerebral palsy

Medicare Risk Adjustment (HCC)Billing

G80.4 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.

CMS-HCC V28 Category (Payment Model)
HCC 192— Cerebral Palsy, Except Quadriplegic
Payment HCC · PY 2027 one of 9 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+0.314
community, non-dual, aged · ranges 0.000–0.314 across segments
Hierarchy
Superseded by HCC 191
a more severe related category takes the payment when both are reported
Prior Model (CMS-HCC V24)
HCC 74
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 74 · ESRD (V21): HCC 74 · ESRD (V24): HCC 74
ESRD V21 weights: 0.036 dialysis, 0.000 functioning graft · ESRD V24 weights: 0.057 dialysis, 0.000–0.226 functioning graft
Part D (RxHCC)
Not mapped
G80.4 does not risk-adjust in the RxHCC prescription drug model

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Ataxic cerebral palsy
  • Cerebral ataxia
  • Cerebral paralysis with homolateral ataxia
  • Cerebral paresis with homolateral ataxia
  • Non-progressive cerebellar ataxia
  • Non-spastic cerebral palsy

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to G80.4: its own notes plus those printed at G80 and Chapter 6. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From G80 Cerebral palsy applies to 7 codes
  • hereditary spastic paraplegia (G11.4)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 6 (G00-G99) Diseases of the nervous system applies to 700 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name G80.4, its category, or a range that includes it.

Includes 1

These notes mention G80.4.

  • G83 Other paralytic syndromes
    paralysis (complete) (incomplete), except as in G80-G82 names G80-G82, which includes this code

Excludes1 2

These codes carry an Excludes1 note naming G80.4: they are not reported together with it, unless the two conditions are unrelated.

  • G81 Hemiplegia and hemiparesis
    congenital cerebral palsy (G80.-) names G80.-, which includes this code
  • G82 Paraplegia (paraparesis) and quadriplegia (quadriparesis)
    congenital cerebral palsy (G80.-) names G80.-, which includes this code

Excludes2 1

These codes carry an Excludes2 note naming G80.4: its condition is not part of those codes, and both may be reported when the patient has both.

  • G11 Hereditary ataxia
    cerebral palsy (G80.-) names G80.-, which includes this code

Use Additional Code 1

These codes say to use an additional code from the note, and G80.4 is one of the codes named.

  • Q87.88 CTNNB1 syndrome
    cerebral palsy (G80.-) names G80.-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NVS007
Cerebral palsy
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Ataxic Cerebral Palsy

    the least common subtype of cerebral palsy, in which the individual displays hypotonia, a loss of motor coordination, and an intention tremor. individuals with ataxic cerebral palsy walk very unsteadily, with a wide-based gait.

  • Cerebral Palsy

    a heterogeneous group of nonprogressive motor disorders caused by chronic brain injuries that originate in the prenatal period, perinatal period, or first few years of life. the four major subtypes are spastic, athetoid, ataxic, and mixed cerebral palsy, with spastic forms being the most common. the motor disorder may range from difficulties with fine motor control to severe spasticity (see muscle spasticity) in all limbs. spastic diplegia (little disease) is the most common subtype, and is characterized by spasticity that is more prominent in the legs than in the arms. pathologically, this condition may be associated with leukomalacia, periventricular. (from dev med child neurol 1998 aug;40(8):520-7)

Patient EducationClinical

Cerebral Palsy

Cerebral palsy (CP) is a group of neurologic disorders that cause problems with movement, balance, and posture. The first part of the name, cerebral, means having to do with the brain. The second part, palsy, means weakness or problems with using the muscles.

The full article covers:

  • What is cerebral palsy (CP)?
  • What are the types of cerebral palsy (CP)?
  • What causes cerebral palsy (CP)?
  • Who is more likely to develop cerebral palsy (CP)?
  • What are the signs of cerebral palsy (CP)?
  • How is cerebral palsy (CP) diagnosed?
  • What are the treatments for cerebral palsy (CP)?
  • Can cerebral palsy (CP) be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert G80.4 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
343.8 Cerebral palsy NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About G80.4Overview

What is the ICD-10 code for ataxic cerebral palsy?

The ICD-10-CM code for ataxic cerebral palsy is G80.4 (sometimes written as G804). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is G80.4 (Cerebral palsy) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report ataxic cerebral palsy on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does G80.4 group to?

When ataxic cerebral palsy is the principal diagnosis on an inpatient stay, it groups to MS-DRG 91, 92, 93, with relative weights from 0.7783 to 1.7050 depending on complications. Higher weights mean higher Medicare reimbursement.

Can G80.4 be reported with G11.4?

Not as a rule. The Excludes1 note at G80, which applies to G80.4, lists "hereditary spastic paraplegia (G11.4)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What is the ICD-9 equivalent of G80.4?

Under the General Equivalence Mappings, ataxic cerebral palsy converts to ICD-9-CM 343.8 (cerebral palsy NEC). The mapping is approximate, so confirm the match fits the documentation.

What HCC is G80.4?

G80.4 (ataxic cerebral palsy) maps to CMS-HCC Category 192 (Cerebral Palsy, Except Quadriplegic), commonly written as HCC 192, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 74 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. It does not map to any RxHCC in the Part D prescription drug model.

Does G80.4 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, G80.4 adds a risk adjustment factor of about 0.314 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.000 to 0.314 depending on the payment segment). A more severe related category (HCC 191) supersedes it when both are reported. See the full factor table on the HCC 192 category page.