ICD-10 Code G40.842 – KCNQ2-related epilepsy, not intractable, without status epilepticus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G40.842 – KCNQ2-related epilepsy, not intractable, without status epilepticus
What it is
This code identifies epilepsy caused by a KCNQ2 gene-related disorder that is not intractable and has no status epilepticus. Use it when documentation clearly links the seizure disorder to KCNQ2.
Clinical signs
Clinical features vary; refer to documentation. Commonly, records describe recurrent seizures and an epilepsy diagnosis with genetic attribution to KCNQ2, without evidence of refractory seizures or status epilepticus.
When to use this code
Use this code when the provider documents KCNQ2-related epilepsy and states the condition is not intractable. It also applies when the chart specifies no status epilepticus. If the genetic cause is implied but not confirmed, check documentation before coding.
Do not use for
Do not use this code if the epilepsy is documented as intractable or if status epilepticus is present. Also avoid it when KCNQ2 is not supported in the record; check documentation.
Coding tip
Code the genetic etiology only when the provider explicitly documents the KCNQ2 link and the seizure severity details.