ICD-10 G40.42
Billable / Specific HCC v28: 79Cyclin-Dependent Kinase-Like 5 Deficiency Disorder
About ICD-10-CM G40.42
ICD-10-CM code G40.42 represents Cyclin-Dependent Kinase-Like 5 Deficiency Disorder. This is a billable/specific code in the Nervous System chapter (block G40). The 2026 edition of ICD-10-CM G40.42 became effective on October 1, 2025.
Coding Tips for G40.42
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
G40.42 is a CMS-HCC v28 risk-adjustment code (category 79). To count for the patient Risk Adjustment Factor (RAF), document the diagnosis with MEAT language each calendar year: Monitored, Evaluated, Assessed, Treated. A diagnosis on the problem list alone does not satisfy CMS RADV audit standards. Include the diagnosis in the assessment with current status and current treatment plan.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under G40.42. Per CMS ICD-10-CM Tabular 2026.
- CDKL5
Use Additional Code
When coding G40.42, also report these additional codes when applicable.
- code, if known, to identify associated manifestations, such as:
- cortical blindness (H47.61-)
- global developmental delay (F88)
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Medicare LCD Coverage for G40.42
Local Coverage Determinations (LCDs) from CMS MACs that list G40.42 as a covered diagnosis.
Showing top 10 of 220 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing G40.42.
5 Medicare
CPT Codes Commonly Billed with G40.42
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 95711 CMS LCD: Billing and Coding: EEG � Ambulatory Monitoring CMS LCD
- 95714 CMS LCD: Billing and Coding: EEG � Ambulatory Monitoring CMS LCD
- 95726 CMS LCD: Billing and Coding: EEG � Ambulatory Monitoring CMS LCD
- 95709 CMS LCD: Billing and Coding: EEG � Ambulatory Monitoring CMS LCD
- 95723 CMS LCD: Billing and Coding: EEG � Ambulatory Monitoring CMS LCD
- 95710 CMS LCD: Billing and Coding: EEG � Ambulatory Monitoring CMS LCD
- 95716 CMS LCD: Billing and Coding: EEG � Ambulatory Monitoring CMS LCD
- 95707 CMS LCD: Billing and Coding: EEG � Ambulatory Monitoring CMS LCD
- 95712 CMS LCD: Billing and Coding: EEG � Ambulatory Monitoring CMS LCD
- 95724 CMS LCD: Billing and Coding: EEG � Ambulatory Monitoring CMS LCD
Codes Adjacent To G40.42
Other codes in section G40-G47 (Episodic and paroxysmal disorders).
ICD-10 G40.42, Billing FAQ
Is ICD-10 code G40.42 billable? +
Yes, G40.42 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to G40.42? +
ICD-10 G40.42 includes: CDKL5.
Does G40.42 affect Medicare Advantage HCC risk adjustment? +
Yes. G40.42 maps to CMS-HCC v28 category 79. Capture this diagnosis annually for accurate Medicare Advantage risk score.
What CPT codes are commonly billed with G40.42? +
Procedures frequently paired with G40.42 include: 95711, 95714, 95726, 95709, 95723.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on July 16, 2026.
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