2023 ICD-10-CM Diagnosis Code G40.42

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Cyclin-Dependent Kinase-Like 5 Deficiency Disorder

    2021 - New Code 2022 2023 Billable/Specific Code
  • G40.42 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
  • The 2023 edition of ICD-10-CM G40.42 became effective on October 1, 2022.
  • This is the American ICD-10-CM version of G40.42 - other international versions of ICD-10 G40.42 may differ.
Applicable To
  • CDKL5
Use Additional
Use Additional Help
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation. In most cases the manifestation codes will have in the code title, "in diseases classified elsewhere." Codes with this title are a component of the etiology/manifestation convention. The code title indicates that it is a manifestation code. "In diseases classified elsewhere" codes are never permitted to be used as first listed or principle diagnosis codes. They must be used in conjunction with an underlying condition code and they must be listed following the underlying condition.
  • code, if known, to identify associated manifestations, such as:
  • cortical blindness (
    ICD-10-CM Diagnosis Code H47.61

    Cortical blindness

      2016 2017 2018 2019 2020 2021 2022 2023 Non-Billable/Non-Specific Code
  • global developmental delay (
    ICD-10-CM Diagnosis Code F88

    Other disorders of psychological development

      2016 2017 2018 2019 2020 2021 2022 2023 Billable/Specific Code
    Applicable To
    • Developmental agnosia
    • Global developmental delay
    • Other specified neurodevelopmental disorder
The following code(s) above G40.42 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to G40.42:
  • G00-G99
    2023 ICD-10-CM Range G00-G99

    Diseases of the nervous system

    Type 2 Excludes
    • certain conditions originating in the perinatal period (P04-P96)
    • certain infectious and parasitic diseases (A00-B99)
    • complications of pregnancy, childbirth and the puerperium (O00-O9A)
    • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
    • endocrine, nutritional and metabolic diseases (E00-E88)
    • injury, poisoning and certain other consequences of external causes (S00-T88)
    • neoplasms (C00-D49)
    • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
    Diseases of the nervous system
  • G40
    ICD-10-CM Diagnosis Code G40

    Epilepsy and recurrent seizures

      2016 2017 2018 2019 2020 2021 2022 2023 Non-Billable/Non-Specific Code
    • the following terms are to be considered equivalent to intractable: pharmacoresistant (pharmacologically resistant), treatment resistant, refractory (medically) and poorly controlled
    Type 1 Excludes
    • conversion disorder with seizures (F44.5)
    • convulsions NOS (R56.9)
    • post traumatic seizures (R56.1)
    • seizure (convulsive) NOS (R56.9)
    • seizure of newborn (P90)
    Type 2 Excludes
    Epilepsy and recurrent seizures
  • G40.4
    ICD-10-CM Diagnosis Code G40.4

    Other generalized epilepsy and epileptic syndromes

      2016 2017 2018 2019 2020 2021 2022 2023 Non-Billable/Non-Specific Code
    Applicable To
    • Epilepsy with grand mal seizures on awakening
    • Epilepsy with myoclonic absences
    • Epilepsy with myoclonic-astatic seizures
    • Grand mal seizure NOS
    • Nonspecific atonic epileptic seizures
    • Nonspecific clonic epileptic seizures
    • Nonspecific myoclonic epileptic seizures
    • Nonspecific tonic epileptic seizures
    • Nonspecific tonic-clonic epileptic seizures
    • Symptomatic early myoclonic encephalopathy
    Other generalized epilepsy and epileptic syndromes
ICD-10-CM G40.42 is grouped within Diagnostic Related Group(s) (MS-DRG v40.0):
  • 023 Craniotomy with major device implant or acute complex cns principal diagnosis with mcc or chemotherapy implant or epilepsy with neurostimulator
  • 100 Seizures with mcc
  • 101 Seizures without mcc
Code History
  • 2021 (effective 10/1/2020): New code
  • 2022 (effective 10/1/2021): No change
  • 2023 (effective 10/1/2022): No change

Diagnosis Index entries containing back-references to G40.42:
  • CDKL5 G40.42 (Cyclin-Dependent Kinase-Like 5 Deficiency Disorder)
  • Disorder (of) - see also Disease
    • Cyclin-Dependent Kinase-Like 5 Deficiency G40.42 (CDKL5)

ICD-10-CM Codes Adjacent To G40.42
G40.B1 Juvenile myoclonic epilepsy, intractable
G40.B11 …… with status epilepticus
G40.B19 …… without status epilepticus
G40.4 Other generalized epilepsy and epileptic syndromes
G40.40 Other generalized epilepsy and epileptic syndromes, not intractable
G40.401 …… with status epilepticus
G40.409 …… without status epilepticus
G40.41 Other generalized epilepsy and epileptic syndromes, intractable
G40.411 …… with status epilepticus
G40.419 …… without status epilepticus
G40.42 Cyclin-Dependent Kinase-Like 5 Deficiency Disorder
G40.5 Epileptic seizures related to external causes
G40.50 Epileptic seizures related to external causes, not intractable
G40.501 …… with status epilepticus
G40.509 …… without status epilepticus
G40.8 Other epilepsy and recurrent seizures
G40.80 Other epilepsy
G40.801 …… not intractable, with status epilepticus
G40.802 …… not intractable, without status epilepticus
G40.803 …… intractable, with status epilepticus
G40.804 …… intractable, without status epilepticus

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.