ICD-10 Code G11.9 – Hereditary ataxia, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G11.9 – Hereditary ataxia, unspecified
What it is
G11.9 identifies a hereditary ataxia when the specific inherited subtype is not documented. It indicates a genetic disorder affecting coordination, balance, or gait, but the chart does not name the exact syndrome.
Clinical signs
Common findings include unsteady gait, poor coordination, and difficulty with fine motor tasks. Clinical features vary; refer to documentation for the family history, neurologic exam, and any named ataxia syndrome.
When to use this code
Use G11.9 when the provider documents hereditary ataxia, familial ataxia, or an inherited coordination disorder without a more specific diagnosis. It also fits when the record confirms a genetic ataxia but the subtype is not yet identified. Code the documented condition, not symptoms alone.
Do not use for
Do not use this code for acquired ataxia, medication-related ataxia, or ataxia from stroke, infection, or intoxication. If a specific hereditary ataxia is documented, choose that code instead.
Coding tip
If the note says “hereditary ataxia” but names no subtype, G11.9 is appropriate; if the subtype appears elsewhere in the record, verify before coding.