G11.3 vs Q85
G11.3 (Cerebellar ataxia with defective DNA repair) compared with Q85 (Phakomatoses, not elsewhere classified), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. Q85 carries an Excludes1 note covering G11.3: “ataxia telangiectasia [Louis-Bar] (G11.3)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| G11.3Cerebellar ataxia with defective DNA repair | Q85Phakomatoses, not elsewhere classified | |
|---|---|---|
| Billing status | Billable | Non-billable header |
| Classification | G00-G99 — Diseases of the Nervous System (G00-G99) | Q00-Q99 — Congenital Malformations, Deformations and Chromosomal Abnormalities (Q00-Q99) |
| Definition | Cerebellar ataxia with defective DNA repair is a billable ICD-10-CM diagnosis code (G11.3). | Phakomatoses, not elsewhere classified is a non-billable ICD-10-CM category code (Q85). |
| Includes | Ataxia telangiectasia [Louis-Bar] | — |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources