G11.8 ICD-10-CM Code: Other hereditary ataxias

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for G11.8 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on G11.8 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for G11.8

MedCoder structured workflow — derived from this code’s own official record

Before you code G11.8

1. “Other” (NEC) means the condition is specified in the record but no dedicated code captures it. Confirm the documented form is not one a sibling code names before settling on G11.8; if the record states no specifics at all, the unspecified sibling applies instead. “Other” codes are for documented conditions the classification gives no specific code; “unspecified” codes are for records lacking the detail (Guidelines I.A.9.a, I.A.9.b).

   ReviewG11.0, G11.1, G11.2, G11.3, G11.4, G11.5, G11.6

   See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

Documentation check

The provider’s diagnostic statement

Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

The associated condition or complication

Whether the associated condition the title names is documented; the “with” convention presumes some links, and a provider statement that the conditions are unrelated defeats it (Guidelines I.A.15).

Any detail beyond this code’s title

What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

• Excludes2 — not part of G11.8(3 notes)

  Coding workflow: The conditions named in this note are not included in G11.8. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  CompareG80, G60

  See the official tabular notes · Guidelines I.A.12.b

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Indexed Clinical Terms (2)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

• Ataxia, ataxy, ataxic, hereditary, specified NEC
• Disease, diseased, spinocerebellar (hereditary), specified NEC

Don’t confuse G11.8 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of G11.8 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• G11.9— Specificity relationship (Review)

  Overlapping diagnoses in the same category.

  Overlapping codes in the same category — the documentation decides which is the more specific fit.

  What moves you there: A record that documents no more than “Hereditary ataxia, unspecified” takes G11.9; specificity in the record moves it back here.

  Full comparison: G11.8 vs G11.9 →

• G80— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of cerebral palsy adds G80; it is not part of this code and both may be reported when both are documented.

  Full comparison: G11.8 vs G80 →

• G60— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of hereditary and idiopathic neuropathy adds G60; it is not part of this code and both may be reported when both are documented.

  Full comparison: G11.8 vs G60 →

• E70— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of metabolic disorders adds E70; it is not part of this code and both may be reported when both are documented.

  Full comparison: G11.8 vs E70 →

• E88— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of metabolic disorders adds E88; it is not part of this code and both may be reported when both are documented.

  Full comparison: G11.8 vs E88 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name G11.8 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 2 Excludes1 notes: R26 — Abnormalities of gait and mobility (via G11.-), R27 — Other lack of coordination (via G11.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 175 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 058 (MDC 01), DRG 059 (MDC 01), DRG 060 (MDC 01).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):NVS006 — Other nervous system disorders (often hereditary or degenerative) (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

G10 — Huntington's disease, G11.0 — Congenital nonprogressive ataxia, G11.10 — Early-onset cerebellar ataxia, unspecified, G11.11 — Friedreich ataxia, G11.19 — Other early-onset cerebellar ataxia, G11.2 — Late-onset cerebellar ataxia, 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, G11.9 — Hereditary ataxia, unspecified, G12.0 — Infantile spinal muscular atrophy, type I [Werdnig-Hoffman], G12.1 — Other inherited spinal muscular atrophy, G12.20 — Motor neuron disease, unspecified, G12.21 — Amyotrophic lateral sclerosis, G12.22 — Progressive bulbar palsy, G12.23 — Primary lateral sclerosis, G12.24 — Familial motor neuron disease, G12.25 — Progressive spinal muscle atrophy, G12.29 — Other motor neuron disease, +154 more

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Friedreich and Other Hereditary Ataxias; Huntington Disease) for risk-adjusted payment.

G10 — Huntington's disease, G11.0 — Congenital nonprogressive ataxia, G11.10 — Early-onset cerebellar ataxia, unspecified, G11.11 — Friedreich ataxia, G11.19 — Other early-onset cerebellar ataxia, G11.2 — Late-onset cerebellar ataxia, 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, G11.9 — Hereditary ataxia, unspecified, G31.80 — Leukodystrophy, unspecified, G90.B — LMNB1-related autosomal dominant leukodystrophy, G93.42 — Megalencephalic leukoencephalopathy with subcortical cysts, G93.43 — Leukoencephalopathy with calcifications and cysts, G93.44 — Adult-onset leukodystrophy with axonal spheroids

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Other nervous system disorders (often hereditary or degenerative)).

G11.0 — Congenital nonprogressive ataxia, G11.1 — Early-onset cerebellar ataxia, G11.10 — Early-onset cerebellar ataxia, unspecified, G11.11 — Friedreich ataxia, G11.19 — Other early-onset cerebellar ataxia, G11.2 — Late-onset cerebellar ataxia, 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, G11.9 — Hereditary ataxia, unspecified, G12.0 — Infantile spinal muscular atrophy, type I [Werdnig-Hoffman], G12.1 — Other inherited spinal muscular atrophy, G12.20 — Motor neuron disease, unspecified, G12.21 — Amyotrophic lateral sclerosis, G12.22 — Progressive bulbar palsy, G12.23 — Primary lateral sclerosis, G12.24 — Familial motor neuron disease, G12.25 — Progressive spinal muscle atrophy, G12.29 — Other motor neuron disease, +83 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Ataxia, ataxy, ataxic”; these codes share that main term but sit in a different category of the Tabular List.

A52.11 — Tabes dorsalis (locomotor), D49.9 — Neoplasm of unspecified behavior of unspecified site (cerebellar, in, neoplastic disease), E03.9 — Hypothyroidism, unspecified (cerebellar, in, myxedema), F44.4 — Conversion disorder with motor symptom or deficit (hysterical), G31.2 — Degeneration of nervous system due to alcohol (cerebellar, alcoholic), G32.81 — Cerebellar ataxia in diseases classified elsewhere (cerebellar, in, specified disease NEC), G60.0 — Hereditary motor and sensory neuropathy (Roussy-Lévy), G60.2 — Neuropathy in association with hereditary ataxia (hereditary, with neuropathy), I69.093 — Ataxia following nontraumatic subarachnoid hemorrhage (following, cerebrovascular disease, subarachnoid hemorrhage), I69.193 — Ataxia following nontraumatic intracerebral hemorrhage (following, cerebrovascular disease, intracerebral hemorrhage), I69.293 — Ataxia following other nontraumatic intracranial hemorrhage (following, cerebrovascular disease, nontraumatic intracranial hemorrhage NEC), I69.393 — Ataxia following cerebral infarction (following, cerebrovascular disease, cerebral infarction), I69.893 — Ataxia following other cerebrovascular disease (following, cerebrovascular disease, specified disease NEC), I69.993 — Ataxia following unspecified cerebrovascular disease (following, cerebrovascular disease), K90.0 — Celiac disease (gluten, with celiac disease), M35.9 — Systemic involvement of connective tissue, unspecified (gluten), R26.0 — Ataxic gait (gait), R27.0 — Ataxia, unspecified, R27.8 — Other lack of coordination (acute)

Contextual Map

Every relationship of G11.8 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run G11.8 with these 2 related codes in Claim Check

Hierarchy

• G00-G99 — Chapter 6: Diseases of the Nervous System (G00-G99) (G00-G99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G10-G14 — Systemic atrophies primarily affecting the central nervous system[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes1 notes

• R26 — Abnormalities of gait and mobility[Excludes1](via G11.-): “hereditary ataxia (G11.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• R27 — Other lack of coordination[Excludes1](via G11.-): “hereditary ataxia (G11.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• NVS006 — Other nervous system disorders (often hereditary or degenerative)[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

Risk adjustment (CMS-HCC)

• HCC 200 — Friedreich and Other Hereditary Ataxias; Huntington Disease [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

• CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 058 — MULTIPLE SCLEROSIS AND CEREBELLAR ATAXIA WITH MCC[MS-DRG]: “MULTIPLE SCLEROSIS AND CEREBELLAR ATAXIA WITH MCC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 059 — MULTIPLE SCLEROSIS AND CEREBELLAR ATAXIA WITH CC[MS-DRG]: “MULTIPLE SCLEROSIS AND CEREBELLAR ATAXIA WITH CC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 060 — MULTIPLE SCLEROSIS AND CEREBELLAR ATAXIA WITHOUT CC/MCC[MS-DRG]: “MULTIPLE SCLEROSIS AND CEREBELLAR ATAXIA WITHOUT CC/MCC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 01 — Diseases and Disorders of the Nervous System[MDC crossing]: “Diseases and Disorders of the Nervous System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 8,892 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

• Ataxia, ataxy, ataxic, hereditary, specified NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Disease, diseased, spinocerebellar (hereditary), specified NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (12)

• G11 — Hereditary ataxia[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G11.0 — Congenital nonprogressive ataxia[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G11.1 — Early-onset cerebellar ataxia[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G11.10 — Early-onset cerebellar ataxia, unspecified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G11.11 — Friedreich ataxia[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G11.19 — Other early-onset cerebellar ataxia[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G11.2 — Late-onset cerebellar ataxia[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G11.3 — Cerebellar ataxia with defective DNA repair[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 4 more

Change history

• FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page

Inpatient payment groups Official source data

CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page

Risk adjustment Official source data

2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to G11.8 in its code family, with their registry titles.

• G11.1 — Early-onset cerebellar ataxia
• G11.10 — Early-onset cerebellar ataxia, unspecified
• G11.11 — Friedreich ataxia
• G11.19 — Other early-onset cerebellar ataxia
• G11.2 — Late-onset cerebellar ataxia
• 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
• G11.9 — Hereditary ataxia, unspecified

View all codes in the G11 family