2027 ICD-10-CM Diagnosis Code G31.80Leukodystrophy, unspecified

ICD-10-CM Codes›G00–G99›G30-G32›G31

ICD-10-CM G31.80
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

G31.80 is a billable ICD-10-CM diagnosis code for leukodystrophy, unspecified. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 56 through 57. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other nervous system disorders (often hereditary or degenerative).

For Medicare Advantage risk adjustment, G31.80 maps to CMS-HCC Category 200 (Friedreich and Other Hereditary Ataxias; Huntington Disease) under the V28 model, adding a risk factor of about 0.279 for a community, non-dual, aged beneficiary in payment year 2027.

Code Identity

ICD-10-CM Code
G31.80
Billable Status
Yes — Valid for Submission
Code Describes
Leukodystrophy, unspecified
Short Description
Leukodystrophy, unspecified
Same as the full description in the CMS dataset.
Parent Code
G31.8
Other specified degenerative diseases of nervous system

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG30-G32Other degenerative diseases of the nervous system
CategoryG31Other degenerative diseases of nervous system, not elsewhere classified
This CodeG31.80Leukodystrophy, unspecified

Medicare Risk Adjustment (HCC)Billing

G31.80 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 200— Friedreich and Other Hereditary Ataxias; Huntington Disease
Payment HCC · PY 2027 one of 17 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+0.279
community, non-dual, aged · ranges 0.000–0.428 across segments
Hierarchy
Top of its hierarchy
HCC 200 is not superseded by any other condition category
Prior Model (CMS-HCC V24)
HCC 52
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
ESRD (V21): HCC 52 · ESRD (V24): HCC 52
ESRD V21 weights: 0.045 dialysis, 0.000–0.328 functioning graft · ESRD V24 weights: 0.042 dialysis, 0.000–0.399 functioning graft
Part D (RxHCC)
Not mapped
G31.80 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.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to G31.80: its own notes plus those printed at G31 and Chapter 6. A note printed at a category, block or chapter applies to every code under it.

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 G31 Other degenerative diseases of nervous system, not elsewhere classified applies to 14 codes
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)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From G31 Other degenerative diseases of nervous system, not elsewhere classified applies to 14 codes

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

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name G31.80, its category, or a range that includes it.

Use Additional Code 1

These codes say to use an additional code from the note, and G31.80 is one of the codes named.

  • G31 Other degenerative diseases of nervous system, not elsewhere classified
    code, if applicable, for codes G31.0-G31.83, G31.85-G31.9, to identify: names G31.0-G31.83, 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 NVS006
Other nervous system disorders (often hereditary or degenerative)
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Leukodystrophy

    a group of rare genetic neurodegenerative disorders that affect infants and children. these disorders are characterized by metabolic abnormalities in the development of the myelin sheaths in the white matter. clinical signs and symptoms include developmental delays, mental retardation, dementia, seizures, loss of motor skills, and muscle weakness. representative examples include metachromatic leukodystrophy, krabbe disease, canavan disease, and alexander disease.

Patient EducationClinical

Leukodystrophies

Leukodystrophies are a group of rare genetic disorders that affect the central nervous system (CNS). The CNS is made up of your brain and spinal cord. Leukodystrophies damage the white matter of your CNS. The white matter includes:

The full article covers:

  • What are leukodystrophies?
  • What causes leukodystrophies?
  • What are the symptoms of leukodystrophies?
  • How are leukodystrophies diagnosed?
  • What are the treatments for leukodystrophies?

Read the full article at MedlinePlus

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

Code History & ChangesHistory

Replacement G31.80 replaces the following previously assigned code(s):

  • G31.89 - Other specified degenerative diseases of nervous system
FY 2024AddedAdded to the ICD-10-CM code setEffective October 1, 2023.
FY 2025–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About G31.80Overview

What is the ICD-10 code for leukodystrophy, unspecified?

The ICD-10-CM code for leukodystrophy, unspecified is G31.80 (sometimes written as G3180). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is G31.80 (Other specified degenerative diseases of nervous system) a billable code?

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

What MS-DRG does G31.80 group to?

When leukodystrophy, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 57, 56, with relative weights from 1.2835 to 2.2649 depending on complications. Higher weights mean higher Medicare reimbursement.

Does G31.80 need an additional code?

When the condition applies, yes. The Use Additional Code note at G31, which applies to G31.80, reads: code, if applicable, for codes G31.0-G31.83, G31.85-G31.9, to identify: dementia with anxiety (F02.84, F02.A4, F02.B4, F02.C4); dementia with behavioral disturbance (F02.81-, F02.A1-, F02.B1-, F02.C1-); dementia with mood disturbance (F02.83, F02.A3, F02.B3, F02.C3); dementia with psychotic disturbance (F02.82, F02.A2, F02.B2, F02.C2); dementia without behavioral disturbance (F02.80, F02.A0, F02.B0, F02.C0); and 1 more listed in the Instructional Notes section. The additional code is reported after G31.80.

What HCC is G31.80?

G31.80 (leukodystrophy, unspecified) maps to CMS-HCC Category 200 (Friedreich and Other Hereditary Ataxias; Huntington Disease), commonly written as HCC 200, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 52 under the retired V24 model. It also maps in the ESRD (V21) and ESRD (V24) models. It does not map to any RxHCC in the Part D prescription drug model.

Does G31.80 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, G31.80 adds a risk adjustment factor of about 0.279 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.000 to 0.428 depending on the payment segment). HCC 200 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 200 category page.