What is ICD-10 code G12.29?

G12.29 is the ICD-10-CM diagnosis code for Other motor neuron disease. It belongs to the ICD-10-CM chapter for diseases of the nervous system (g00-g99). G12.29 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. G12.29 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. G12.29 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. G12.29 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does G12.29 map to under V28?

G12.29 maps to CMS-HCC V28 HCC 190 (Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease, Spinal Muscular Atrophy). The category numbers, labels, and conditions come from the CMS-HCC V28 model file for payment year 2026.

What documentation supports G12.29?

Use this code only when the motor neuron disease is not better specified by other G12 codes (such as ALS, SMA, or progressive bulbar palsy); always document the specific type of motor neuron disease in the medical record for clarity This is a 'catch-all' code, so verify that more specific diagnoses are not applicable before assigning G12.29; consider querying the provider if the documentation is vague about the exact motor neuron disease type For G12.29, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. See the MEAT criteria checklist at /meat-criteria for what Monitor, Evaluate, Assess, or Treat looks like in a note. One mnemonic element does not establish that a diagnosis is reportable.

2026 ICD-10-CM G12.29: Other motor neuron disease

G12.29 maps to CMS-HCC V28 190. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · free HCC coding tools

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Code lookupG12.29

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Systemic atrophies primarily affecting the central nervous system (G10-G14)

G12.29

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Other motor neuron disease

This code represents a motor neuron disease that doesn't fit into other specific categories, affecting the nerves that control muscle movement. It includes rare or atypical forms of conditions where muscles gradually weaken due to nerve damage.

Buddy Insight

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 190

Amyotrophic Lateral Sclerosis...

Code-level coefficient reference

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 111

HHS-HCC 111 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 73

Amyotrophic Lateral Sclerosis...

Code-level coefficient reference

RXHCC

Mapped

HCC 154

Amyotrophic Lateral Sclerosis...

Code-level coefficient reference

Code Book Path

Official

G12Spinal muscular atrophy and related syndromes G12.2Motor neuron disease G12.29Other motor neuron disease

Inclusion Terms

Official

No inclusion terms are included in this display for G12.29. Check the code and parent instructions in the Code Book.

Excludes 2

Official

certain conditions originating in the perinatal period (P04-P96)Inherited from G00-G99
certain infectious and parasitic diseases (A00-B99)Inherited from G00-G99
complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from G00-G99
congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Inherited from G00-G99
endocrine, nutritional and metabolic diseases (E00-E88)Inherited from G00-G99
injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from G00-G99
neoplasms (C00-D49)Inherited from G00-G99
symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from G00-G99

Related Codes

Official

G12.20Motor neuron disease, unspecified G12.21Amyotrophic lateral sclerosis G12.22Progressive bulbar palsy G12.23Primary lateral sclerosis G12.24Familial motor neuron disease

Includes

Official

No Includes notes are included in this display for G12.29. Check the code and parent instructions in the Code Book.

Excludes 1

Official

No Excludes 1 notes are included in this display for G12.29. Check the code and parent instructions in the Code Book.

Code First

Official

No Code First sequencing instructions are included in this display for G12.29. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for G12.29. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for G12.29. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Clinical evidence of motor neuron dysfunction (weakness, atrophy, or spasticity)

Documentation of the specific atypical motor neuron disease presentation

Electromyography and nerve conduction study results

Explanation of why the presentation does not fit standard motor neuron disease subtypes

MEAT Support

HCC Buddy guidance

Clinical evidence of motor neuron dysfunction (weakness, atrophy, or spasticity)

Documentation of the specific atypical motor neuron disease presentation

Electromyography and nerve conduction study results

Explanation of why the presentation does not fit standard motor neuron disease subtypes

Audit Caution

HCC Buddy guidance

Using this catch-all code without verifying that more specific motor neuron disease codes do not apply

Confusing 'other specified' (G12.29) with 'unspecified' (G12.20) — use G12.29 when the type is known but atypical

Not querying the provider about whether the presentation has evolved into a classifiable subtype

Failing to document the specific atypical features that preclude assignment of a standard motor neuron disease code

Common Mistakes

HCC Buddy guidance

G12.21 — Amyotrophic lateral sclerosis: the most common motor neuron disease; confirm it does not apply before using G12.29

G12.20 — Motor neuron disease, unspecified: use only when no specific type can be determined at all

G12.23 — Primary lateral sclerosis: specific upper motor neuron subtype

G12.25 — Progressive spinal muscle atrophy: specific lower motor neuron subtype

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is G12.29 an HCC code?

Yes. G12.29 (Other motor neuron disease) maps to HCC 190, Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease, Spinal Muscular Atrophy under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 1.175. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: G12.29 is billable and maps to V28 HCC 190, Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease, Spinal Muscular Atrophy. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: G12.29
Description: Other motor neuron disease
HCC (V28): HCC 190 — Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease, Spinal Muscular Atrophy
RAF reference coefficient: 1.175
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 190, Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease, Spinal Muscular Atrophy

1.175

ESRDHCC 73, Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease

Not separately weighted

RxHCCHCC 154, Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work G12.29 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for G12.29

For G12.29, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Coder workflow notes

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What This Code Means

G12.29 is the ICD-10-CM diagnosis code for other motor neuron disease. This code represents a motor neuron disease that doesn't fit into other specific categories, affecting the nerves that control muscle movement. It includes rare or atypical forms of conditions where muscles gradually weaken due to nerve damage. G12.29 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering systemic atrophies primarily affecting the central nervous system (g10-g14).

Under the CMS-HCC V28 risk adjustment model, G12.29 maps to Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease, Spinal Muscular Atrophy (HCC 190) with a source-labeled community, non-dual, aged reference coefficient of 1.175. No V24 mapping is shown for G12.29; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Use this code only when the motor neuron disease is not better specified by other G12 codes (such as ALS, SMA, or progressive bulbar palsy); always document the specific type of motor neuron disease in the medical record for clarity. For G12.29, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for G12.29 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Use this code only when the motor neuron disease is not better specified by other G12 codes (such as ALS, SMA, or progressive bulbar palsy); always document the specific type of motor neuron disease in the medical record for clarity
•This is a 'catch-all' code, so verify that more specific diagnoses are not applicable before assigning G12.29; consider querying the provider if the documentation is vague about the exact motor neuron disease type

Clinical Significance

Other motor neuron disease captures rare or atypical forms of motor neuron degeneration that do not fit established subtypes like amyotrophic lateral sclerosis, primary lateral sclerosis, or progressive bulbar palsy. These conditions still carry significant morbidity and mortality, requiring specialized neurological management and symptom-directed care.

Documentation Requirements

✓Clinical evidence of motor neuron dysfunction (weakness, atrophy, or spasticity)
✓Documentation of the specific atypical motor neuron disease presentation
✓Electromyography and nerve conduction study results
✓Explanation of why the presentation does not fit standard motor neuron disease subtypes
✓Imaging studies (MRI brain and spine) to exclude structural causes
✓Provider statement confirming motor neuron disease diagnosis

Commonly Confused Codes

•G12.21: Amyotrophic lateral sclerosis: the most common motor neuron disease; confirm it does not apply before using G12.29
•G12.20: Motor neuron disease, unspecified: use only when no specific type can be determined at all
•G12.23: Primary lateral sclerosis: specific upper motor neuron subtype
•G12.25: Progressive spinal muscle atrophy: specific lower motor neuron subtype