G12.21 Amyotrophic lateral sclerosis

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Risk adjustment (HCC)

• CMS-HCC V28: HCC 190 — Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease, Spinal Muscular Atrophy
• CMS-HCC V22: HCC 73 — Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease
• RxHCC V08: HCC 154 — Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease
• ESRD V24: HCC 73

MS-DRG index

Defines the logic of DRG(s) 056-057 in MDC 01.

Approximate ICD-9-CM (GEMs)

• 335.20 Amyotrophic lateral sclerosis (approximate)
• 335.21 Progressive muscular atrophy (approximate)

Medicare Code Edits (MCE v43.1 (April 2026))

• Adult diagnoses (age 15 through 124): Age conflict edit. These diagnoses are clinically expected only in patients age 15 through 124.

Code annotations containing back-references to G12.21

Back-references to G12.21

• Code First: F48.2 Pseudobulbar affect ("amyotrophic lateral sclerosis (G12.21)")
• Type 1 Excludes: M62.5 Muscle wasting and atrophy, not elsewhere classified ("progressive muscular atrophy (G12.21)")

Diagnosis Index entries for G12.21

• Amyotrophia, amyotrophy, amyotrophic › lateral sclerosis
• Atrophy, atrophic (of) › Duchenne-Aran
• Atrophy, atrophic (of) › muscle, muscular (diffuse) (general) (idiopathic) (primary) › Duchenne-Aran
• Atrophy, atrophic (of) › muscle, muscular (diffuse) (general) (idiopathic) (primary) › progressive (bulbar)
• Atrophy, atrophic (of) › muscle, muscular (diffuse) (general) (idiopathic) (primary) › spinal › Aran-Duchenne
• Disease, diseased › motor neuron (bulbar) (mixed type) (spinal) › amyotrophic lateral sclerosis
• Duchenne-Aran muscular atrophy
• Paralysis, paralytic (complete) (incomplete) › amyotrophic
• Paralysis, paralytic (complete) (incomplete) › muscle, muscular NEC › progressive
• Paralysis, paralytic (complete) (incomplete) › spinal (cord) › progressive
• Sclerosis, sclerotic › amyotrophic (lateral)
• Sclerosis, sclerotic › lateral (amyotrophic) (descending) (spinal)
• Sclerosis, sclerotic › spinal (cord) (progressive) › lateral (amyotrophic)

Nearby codes

• 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
• G12.20 Motor neuron disease, unspecified
• G12.21 Amyotrophic lateral sclerosis (this code)
• 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