2026 ICD-10-CM Diagnosis Code G12.20Motor neuron disease, unspecified

ICD-10-CM Codes›G00–G99›G10-G14›G12

ICD-10-CM G12.20
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G12.20 is a billable ICD-10-CM diagnosis code for motor neuron disease, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other nervous system disorders (often hereditary or degenerative).

Code Identity

ICD-10-CM Code
G12.20
Billable Status
Yes — Valid for Submission
Code Describes
Motor neuron disease, unspecified
Short Description
Motor neuron disease, unspecified
Same as the full description in the CMS dataset.
Parent Code
G12.2
Motor neuron disease

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG10-G14Systemic atrophies primarily affecting the central nervous system
CategoryG12Spinal muscular atrophy and related syndromes
This CodeG12.20Motor neuron disease, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral upper motor neurone lesion
  • Corticospinal motor disease
  • Frontal lobe degeneration with motor neurone disease
  • Lesion of left upper motor neuron
  • Lesion of right upper motor neuron
  • Lower motor neuron disease
  • Mills syndrome
  • Motor neuron disease
  • Motor neuron disease due to and following radiotherapy to spinal cord
  • Motor neuron disease due to gammopathy
  • Motor neuron disease due to hereditary spastic paraplegia
  • Motor neuron disease due to herpes zoster
  • Motor neuron disease due to human immunodeficiency virus infection
  • Motor neuron disease due to lead intoxication
  • Upper motor neuron disease
  • Upper motor neurone lesion

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

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

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

  • Amyotrophic Lateral Sclerosis

    a degenerative disorder affecting upper motor neurons in the brain and lower motor neurons in the brain stem and spinal cord. disease onset is usually after the age of 50 and the process is usually fatal within 3 to 6 years. clinical manifestations include progressive weakness, atrophy, fasciculation, hyperreflexia, dysarthria, dysphagia, and eventual paralysis of respiratory function. pathologic features include the replacement of motor neurons with fibrous astrocytes and atrophy of anterior spinal nerve roots and corticospinal tracts. (from adams et al., principles of neurology, 6th ed, pp1089-94)

  • Motor Neuron Disease

    diseases characterized by a selective degeneration of the motor neurons of the spinal cord, brainstem, or motor cortex. clinical subtypes are distinguished by the major site of degeneration. in amyotrophic lateral sclerosis there is involvement of upper, lower, and brainstem motor neurons. in progressive muscular atrophy and related syndromes (see muscular atrophy, spinal) the motor neurons in the spinal cord are primarily affected. with progressive bulbar palsy (bulbar palsy, progressive), the initial degeneration occurs in the brainstem. in primary lateral sclerosis, the cortical neurons are affected in isolation. (adams et al., principles of neurology, 6th ed, p1089)

Patient EducationClinical

Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a nervous system disease that attacks nerve cells called neurons in your brain and spinal cord. These neurons transmit messages from your brain and spinal cord to your voluntary muscles - the ones you can control, like in your arms and legs. At first, this causes mild muscle problems.

Read the full article at MedlinePlus

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

Convert G12.20 to ICD-9-CMHistory

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

ICD-9-CM
335.29 Motor neuron disease 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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About G12.20Overview

Is G12.20 (Motor neuron disease) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report motor neuron disease, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of G12.20?

Under the General Equivalence Mappings, motor neuron disease, unspecified converts to ICD-9-CM 335.29 (motor neuron disease NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.