G31.86
BillableAlexander disease
HCC Category Mapping
V28HCC 127 — Dementia, Mild or Unspecified
0.464RxHCCHCC 112 — Dementia and Other Specified Brain Disorders
0.000What This Code Means
Alexander disease is a rare inherited neurological disorder that affects the white matter of the brain, causing progressive weakness, loss of coordination, and cognitive decline.
Coding Tips
- •This is a rare genetic disorder; ensure documentation clearly identifies Alexander disease rather than other leukodystrophies
- •May require additional codes for associated symptoms such as seizures, spasticity, or developmental delays
Clinical Significance
Alexander disease is a rare progressive leukodystrophy caused by mutations in the GFAP gene, primarily affecting white matter of the brain. It causes progressive spasticity, seizures, and cognitive decline, with infantile forms being most severe. Accurate coding ensures proper risk adjustment for these patients with high-intensity care needs including neurology, genetics, and rehabilitation services.
Documentation Requirements
- ✓Provider documentation specifically identifying Alexander disease
- ✓Genetic testing confirming GFAP gene mutation
- ✓Neuroimaging (MRI) showing characteristic frontal-predominant white matter abnormalities
- ✓Documentation of clinical features: macrocephaly (infantile form), spasticity, seizures, developmental regression
- ✓Classification of disease form (infantile, juvenile, or adult onset)
- ✓Current treatment plan and multidisciplinary care team involvement
Commonly Confused Codes
G31.80 — Leukodystrophy, unspecified; use only when the specific type of leukodystrophy cannot be determinedE75.25 — Metachromatic leukodystrophy; different genetic leukodystrophy with lysosomal enzyme deficiencyG23.3 — Hypomyelination with atrophy of basal ganglia and cerebellum; different pattern of white matter diseaseG31.89 — Other specified degenerative diseases of nervous system; too nonspecific when Alexander disease is confirmed