KCNQ2-related epilepsy

Not billableICD-10-CM diagnosis code.

This code exists but cannot be submitted on its own. It groups the more specific codes beneath it.

A category header for its whole life, FY2025 onwards. It has never been valid for submission on its own.

Submit one of these 4 more specific codes instead:

G40.841 KCNQ2-related epilepsy, not intractable, with status epilepticus
G40.842 KCNQ2-related epilepsy, not intractable, without status epilepticus
G40.843 KCNQ2-related epilepsy, intractable, with status epilepticus
G40.844 KCNQ2-related epilepsy, intractable, without status epilepticus

What has happened to this code

Every change the publisher made, from 2025 to now.

FY2025 Added to the code set KCNQ2-related epilepsy

Official coding rules

Published by CDC for FY2027. A rule attached to a category binds every code beneath it, so the rules inherited from this code's ancestors are shown with the code they come from.

Inherited from G40 Epilepsy and recurrent seizures

Excludes1 - never coded here

conversion disorder with seizures (F44.5)
convulsions NOS (R56.9)
post traumatic seizures (R56.1)
seizure (convulsive) NOS (R56.9)
seizure of newborn (P90)

Excludes2 - not included here

hippocampal sclerosis (G93.81)
mesial temporal sclerosis (G93.81)
temporal sclerosis (G93.81)
Todd's paralysis (G83.84)

Note

the following terms are to be considered equivalent to intractable: pharmacoresistant (pharmacologically resistant), treatment resistant, refractory (medically) and poorly controlled

How CDC's index refers to this code

Wording from the official alphabetic index. Much of it appears nowhere in the code description, which is why a search for the everyday phrase so often finds nothing.

State > confusional > acute
State > confusional > subacute
Disorder > major neurocognitive
Disorder > neurocognitive > major
Syndrome > brain > acute or subacute
Delirium, delirious > with > dementia
Reaction > organic, acute or subacute
Disorder > neurocognitive > major > in
Disorder > neurocognitive > major > in > with > violent behavior
Disorder > neurocognitive > major > in > with > combative behavior
Disorder > neurocognitive > major > in > with > aggressive behavior
Dementia > in > epilepsy
Dementia > in > epilepsy > with behavioral disturbance

Codes in the same group

Code	Description	Status
G40.80	Other epilepsy	Not billable
G40.81	Lennox-Gastaut syndrome	Not billable
G40.82	Epileptic spasms	Not billable
G40.83	Dravet syndrome	Not billable
G40.89	Other seizures	Valid