ICD-10 Code G40.844 – KCNQ2-related epilepsy, intractable, without status epilepticus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G40.844 – KCNQ2-related epilepsy, intractable, without status epilepticus
What it is
This code identifies epilepsy caused by a KCNQ2 gene-related disorder that is difficult to control with treatment and is not currently in status epilepticus. Use it when the diagnosis is specifically documented as intractable.
Clinical signs
Typical documentation may include recurrent seizures beginning early in life, poor seizure control despite therapy, and a confirmed or suspected KCNQ2-related epilepsy diagnosis. Clinical features vary; refer to documentation.
When to use this code
Use G40.844 when the provider documents KCNQ2-related epilepsy and states that it is intractable. Apply it for ongoing epilepsy visits, neurology follow-up, or inpatient care when the condition is active and seizure control remains poor. Confirm that status epilepticus is not documented.
Do not use for
Do not use this code for controlled KCNQ2-related epilepsy or for seizures not described as epilepsy. Also avoid it when status epilepticus is present or when the record only says “suspected” KCNQ2 disorder without confirmation.
Coding tip
Check the note for both “KCNQ2-related” and “intractable”; if either element is missing, verify the diagnosis before assigning G40.844.