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G12.20 ICD-10-CM Code: Motor neuron disease, unspecified

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Inpatient Payment Groups (MS-DRG)

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0, Appendix B.

  • MS-DRG 056 — DEGENERATIVE NERVOUS SYSTEM DISORDERS WITH MCC (MDC 01)
  • MS-DRG 057 — DEGENERATIVE NERVOUS SYSTEM DISORDERS WITHOUT MCC (MDC 01)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Risk Adjustment (CMS-HCC)

Payment categories this diagnosis maps to under CMS-HCC V28, payment year 2026.

  • HCC 190 — Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease, Spinal Muscular Atrophy

Other models: CMS-HCC V22 HCC 73 · RxHCC V08 HCC 154

Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.

Official Registry Overview & Definition

Motor neuron disease, unspecified is a billable ICD-10-CM diagnosis code (G12.20).

Indexed Clinical Terms (2)

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.

  • Atrophy, atrophic (of), spinal (acute) (cord), paralysis
  • Disease, diseased, motor neuron (bulbar) (mixed type) (spinal)

Change history

No changes recorded for this code — unchanged since the FY2016 baseline of the change ledger.

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.

Relationships & Classification

Potential MS-DRG Relationships (FY2026)

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 111 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 2 MS-DRGs: DRG 056 (MDC 01), DRG 057 (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.

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, G11.8 — Other hereditary ataxias, G11.9 — Hereditary ataxia, unspecified, G12.0 — Infantile spinal muscular atrophy, type I [Werdnig-Hoffman], G12.1 — Other inherited spinal muscular atrophy, 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, G12.8 — Other spinal muscular atrophies and related syndromes, G12.9 — Spinal muscular atrophy, unspecified, G21.0 — Malignant neuroleptic syndrome, G23.0 — Hallervorden-Spatz disease, +288 more

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease, Spinal Muscular Atrophy) for risk-adjusted payment.

G12.0 — Infantile spinal muscular atrophy, type I [Werdnig-Hoffman], G12.1 — Other inherited spinal muscular atrophy, 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, G12.8 — Other spinal muscular atrophies and related syndromes, G12.9 — Spinal muscular atrophy, unspecified

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)).

G11.19 — 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, G11.8 — Other hereditary ataxias, G11.9 — Hereditary ataxia, unspecified, G12.0 — Infantile spinal muscular atrophy, type I [Werdnig-Hoffman], G12.1 — Other inherited spinal muscular atrophy, 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, G12.8 — Other spinal muscular atrophies and related syndromes, G12.9 — Spinal muscular atrophy, unspecified, G21.0 — Malignant neuroleptic syndrome, G21.11 — Neuroleptic induced parkinsonism, +83 more

Contextual Map

Every relationship of G12.20 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.

Hierarchy

  • G00-G99 — Chapter 6: Diseases of the Nervous System (G00-G99) (G00-G99) [Hierarchy]

Clinical classification (CCSR)

  • NVS006 — Other nervous system disorders (often hereditary or degenerative) [CCSR]

Risk adjustment (CMS-HCC)

  • HCC 190 — Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease, Spinal Muscular Atrophy [CMS-HCC]

Potential MS-DRG

  • CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”
  • DRG 056 — DEGENERATIVE NERVOUS SYSTEM DISORDERS WITH MCC [MS-DRG]: “DEGENERATIVE NERVOUS SYSTEM DISORDERS WITH MCC (MDC 01)”
  • DRG 057 — DEGENERATIVE NERVOUS SYSTEM DISORDERS WITHOUT MCC [MS-DRG]: “DEGENERATIVE NERVOUS SYSTEM DISORDERS WITHOUT MCC (MDC 01)”

MDC crossing · procedures (8892)

  • 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.”
  • 0016070 — Bypass Cerebral Ventricle to Nasopharynx with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Nasopharynx with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016071 — Bypass Cerebral Ventricle to Mastoid Sinus with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Mastoid Sinus with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016072 — Bypass Cerebral Ventricle to Atrium with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Atrium with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016073 — Bypass Cerebral Ventricle to Blood Vessel with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Blood Vessel with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016074 — Bypass Cerebral Ventricle to Pleural Cavity with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Pleural Cavity with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • and 8887 more

Index entries

  • Atrophy, atrophic (of), spinal (acute) (cord), paralysis[Index term]
  • Disease, diseased, motor neuron (bulbar) (mixed type) (spinal)[Index term]

Nearest codes (12)

  • G12 — Spinal muscular atrophy and related syndromes [Sibling]
  • G12.0 — Infantile spinal muscular atrophy, type I [Werdnig-Hoffman] [Sibling]
  • G12.1 — Other inherited spinal muscular atrophy [Sibling]
  • G12.2 — Motor neuron disease [Sibling]
  • G12.21 — Amyotrophic lateral sclerosis [Sibling]
  • G12.22 — Progressive bulbar palsy [Sibling]
  • G12.23 — Primary lateral sclerosis [Sibling]
  • G12.24 — Familial motor neuron disease [Sibling]
  • and 4 more

Nearest Codes in This Family

Official ICD-10-CM classifications closest to G12.20 in its code family, with their registry titles.

  • G12 — Spinal muscular atrophy and related syndromes
  • G12.0 — Infantile spinal muscular atrophy, type I [Werdnig-Hoffman]
  • G12.1 — Other inherited spinal muscular atrophy
  • G12.2 — Motor neuron disease
  • 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

View all codes in the G12 family