2026 ICD-10-CM Diagnosis Code G31.89Other specified degenerative diseases of nervous system

ICD-10-CM Codes›G00–G99›G30-G32›G31

ICD-10-CM G31.89
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G31.89 is a billable ICD-10-CM diagnosis code for other specified degenerative diseases of nervous system. 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
G31.89
Billable Status
Yes — Valid for Submission
Code Describes
Other specified degenerative diseases of nervous system
Short Description
Other specified degenerative diseases of nervous system
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 CodeG31.89Other specified degenerative diseases of nervous system

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • 3-Methylglutaconic aciduria type 4
  • Acquired cerebellar atrophy
  • Acute cerebellar syndrome
  • Argyrophilic grain disease
  • Arteriopathic granular atrophy of cerebral cortex
  • Atrophy of cerebellar vermis
  • Atrophy of corticospinal tract
  • Atrophy of pyramidal tract
  • Autoimmune cerebellar degeneration
  • Autosomal dominant striatal neurodegeneration
  • Autosomal recessive cerebral atrophy
  • Axonal neuropathy
  • Beta-propeller protein-associated neurodegeneration
  • Cerebellar ataxia associated with another disorder
  • Cerebellar deficiency syndrome
  • Cerebral degeneration in childhood
  • Childhood-onset motor and cognitive regression syndrome with extrapyramidal movement disorder
  • Chorea co-occurrent and due to dentatorubropallidoluysian degeneration
  • Chorea co-occurrent and due to Huntington disease-like condition
  • Chorea due to chronic hepatocerebral degeneration
  • Chorea due to hereditary ataxia
  • Chorea due to heredodegenerative disorder
  • Chorea due to Huntington disease-like 1
  • Chorea due to Huntington disease-like 2
  • Chorea due to Huntington disease-like 3
  • Choreoathetosis
  • Chronic hepatocerebral degeneration
  • CLCN6-related childhood-onset progressive neurodegeneration, peripheral neuropathy syndrome
  • Coenzyme A synthase protein associated neurodegeneration
  • Congenital cerebellar cortical atrophy
  • Congenital microcephaly, severe encephalopathy, progressive cerebral atrophy syndrome
  • Corneal cerebellar syndrome
  • Corticostriatal-spinal degeneration
  • Cystic degeneration of brain
  • Dentatorubropallidoluysian degeneration
  • Diffuse atrophy of cerebellum
  • Diffuse atrophy of cerebrum
  • Diffuse cerebral and cerebellar atrophy, intractable seizures, progressive microcephaly syndrome
  • Disorder of valine metabolism
  • Early-onset neurodegeneration, choreoathetoid movement, microcytic anemia due to IREB2 mutation
  • Early-onset progressive diffuse brain atrophy, microcephaly, muscle weakness, optic atrophy syndrome
  • Early-onset progressive encephalopathy, hearing loss, pons hypoplasia, brain atrophy syndrome
  • Early-onset progressive neurodegeneration, blindness, ataxia, spasticity syndrome
  • Fatal post-viral neurodegenerative disorder
  • Fatty acid hydroxylase associated neurodegeneration
  • Generalized dystonia
  • Global brain atrophy
  • Global developmental delay, visual anomalies, progressive cerebellar atrophy, truncal hypotonia syndrome
  • Hereditary acantholytic dermatosis
  • Hereditary cerebellar atrophy
  • Hereditary degenerative disease of central nervous system
  • Huntington disease-like 1
  • Huntington disease-like 3
  • Huntington disease-like syndrome
  • Huntington disease-like syndrome due to C9ORF72 expansions
  • Hypomyelinating leukodystrophy with atrophy of basal ganglia and cerebellum
  • Inborn error of amino acid metabolism
  • Infantile cerebral and cerebellar atrophy with postnatal progressive microcephaly
  • Infantile neuroaxonal dystrophy
  • Infantile neurodegeneration, progressive spasticity, intellectual disability, white matter lesions syndrome
  • Infantile spasms, psychomotor retardation, progressive brain atrophy, basal ganglia disease syndrome
  • Infantile-onset axonal motor and sensory neuropathy, optic atrophy, neurodegenerative syndrome
  • Juvenile cerebellar degeneration AND myoclonus
  • Keratosis follicularis, dwarfism, cerebral atrophy syndrome
  • Kufor Rakeb syndrome
  • Late cortical cerebellar atrophy
  • Late infantile and juvenile neuroaxonal dystrophy
  • MEGDEL syndrome
  • MEPAN syndrome
  • Mitochondrial membrane protein associated neurodegeneration
  • NADHX dehydratase deficiency
  • NADHX epimerase deficiency
  • Neuroaxonal dystrophy
  • Neurodegeneration due to 3-hydroxyisobutyryl coenzyme A hydrolase deficiency
  • Neurodevelopmental delay, seizures, ophthalmic anomalies, osteopenia, cerebellar atrophy syndrome
  • Olivopontocerebellar atrophy and deafness
  • Olivopontocerebellar degeneration
  • PCNA-related progressive neurodegenerative photosensitivity syndrome
  • Pineal degeneration
  • PRKAR1B-related neurodegenerative dementia with intermediate filaments
  • Progressive cerebello-cerebral atrophy
  • Progressive chorea
  • Progressive encephalopathy with edema, hypsarrhythmia, and optic atrophy-like syndrome
  • Progressive neuronal degeneration of childhood
  • Progressive neuronal degeneration without liver cirrhosis
  • Second cranial nerve finding
  • Severe neurodegenerative syndrome with lipodystrophy
  • Sporadic cerebellar degeneration
  • Synucleinopathy
  • TUBB4A-related leukodystrophy
  • Type 1 diabetes mellitus, central and peripheral neurodegeneration syndrome
  • USP18 deficiency
  • X-linked neurodegenerative syndrome Bertini type
  • X-linked neurodegenerative syndrome Hamel type

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.

    • Degeneration, degenerative
      • brain (cortical) (progressive)
        • childhood
          • specified NEC
    • Degeneration, degenerative
      • brain (cortical) (progressive)
        • cystic
    • Degeneration, degenerative
      • cortical (cerebellar) (parenchymatous)
    • Degeneration, degenerative
      • nervous system
        • fatty
    • Degeneration, degenerative
      • nervous system
        • specified NEC
    • Degeneration, degenerative
      • spinal (cord)
    • Degeneration, degenerative
      • spinal (cord)
        • familial NEC
    • Degeneration, degenerative
      • spinal (cord)
        • fatty
    • Dystrophy, dystrophia
      • infantile neuraxonal
    • Seitelberger's syndrome(infantile neuraxonal dystrophy)
    • Syndrome
      • Seitelberger's

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

  • Infantile Neuroaxonal Dystrophy

    a rare autosomal recessive neurodegenerative disorder caused by mutations in the pla2g6 gene. it is characterized by the development of swellings called spehroids along the axons of the central nervous system. signs and symptoms appear early in life and include movement difficulties, muscle hypotonia and spasticity, and dementia.

  • Acute Motor and Sensory Axonal Neuropathy|Acute Motor And Sensory Axonal Neuropathy|Acute Motor-Sensory Axonal Neuropathy|Acute Motor-Sensory Axonal Neuropathy

    a subtype of guillain-barre syndrome that targets sensory motor axons, and is characterized by acute onset of quadriparesis, distal sensory loss, areflexia, and respiratory insufficiency.

  • Acute Motor Axonal Neuropathy|AMAN

    a subtype of guillain-barre syndrome that targets motor axons, and is characterized by symmetric limb weakness, diffuse areflexia, facial and oropharyngeal muscle weakness, and respiratory insufficiency.

  • Axonal Neuropathy

    any nerve disorder affecting the axon of a nerve.

  • GAN wt Allele|GAN1|Giant Axonal Neuropathy (Gigaxonin) Gene|Gigaxonin wt Allele|KLHL16

    human gan wild-type allele is located in the vicinity of 16q24.1 and is approximately 65 kb in length. this allele, which encodes gigaxonin protein, is involved in both ubiquitination and neurofilament structure. mutation of the gene is associated with giant axonal neuropathy.

  • Giant Axonal Neuropathy

    a rare inherited disorder affecting the neurofilaments. it is caused by mutations in the gan gene. it is characterized by the presence of abnormally large nerve cell axons. signs and symptoms include difficulty walking, sensory disturbances, lack of motor coordination and abnormal reflexes in the limbs.

  • Spinocerebellar Ataxia, Autosomal Recessive, with Axonal Neuropathy 2|AOA2|Ataxia with Oculomotor Apraxia Type 2|SCAN2

    an autosomal recessive condition caused by mutation(s) in the setx gene, encoding probable helicase senataxin. it is characterized by juvenile onset progressive cerebellar ataxia, axonal sensorimotor peripheral neuropathy, and increased concentrations of serum alpha-fetoprotein. oculomotor apraxia is common, but is not always present.

Patient EducationClinical

Degenerative Nerve Diseases

Degenerative nerve diseases affect many of your body's activities, such as balance, movement, talking, breathing, and heart function. Many of these diseases are genetic. Sometimes the cause is a medical condition such as alcoholism, a tumor, or a stroke. Other causes may include toxins, chemicals, and viruses.

Read the full article at MedlinePlus

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

Convert G31.89 to ICD-9-CMHistory

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

ICD-9-CM
331.89 Cereb degeneration 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 G31.89Overview

Is G31.89 (Other specified degenerative diseases of nervous system) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other specified degenerative diseases of nervous system on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of G31.89?

Under the General Equivalence Mappings, other specified degenerative diseases of nervous system converts to ICD-9-CM 331.89 (cereb degeneration 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.