ICD-10-CM 2027
ICD-10 code for Alexander disease
From the official ICD-10-CM alphabetic index entry “Disease, diseased › Alexander”. Page updated September 29, 2026.
About coding Alexander disease
The ICD-10-CM code for Alexander disease is G31.86 (Alexander disease).
Within G31.8 (other specified degenerative diseases of nervous system), G31.86 is specifically for Alexander disease. Related codes cover leukodystrophy, unspecified (G31.80), Alpers disease (G31.81), Leigh's disease (G31.82), neurocognitive disorder with Lewy bodies (G31.83), mild cognitive impairment of uncertain or unknown etiology (G31.84), Corticobasal degeneration (G31.85), primary progressive apraxia of speech (G31.87) and other specified degenerative diseases of nervous system (G31.89).
Use an additional code, if applicable, for codes G31.0-G31.83, G31.85-G31.9, to identify: dementia with anxiety (F02.84, F02.A4, F02.B4, F02.C4), dementia with behavioral disturbance (F02.81-, F02.A1-, F02.B1-, F02.C1-), dementia with mood disturbance (F02.83, F02.A3, F02.B3, F02.C3), dementia with psychotic disturbance (F02.82, F02.A2, F02.B2, F02.C2), dementia without behavioral disturbance (F02.80, F02.A0, F02.B0, F02.C0) and 1 more.
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
Common questions about Alexander disease ICD-10 codes
What is the ICD-10 code for Alexander disease?
- G31.86 — Alexander disease.
Is G31.86 billable?
- Yes. G31.86 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can G31.86 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict G31.86 as a principal diagnosis.
Is G31.86 a CC or MCC?
- No. G31.86 is neither a CC nor an MCC under MS-DRG v44.0.