G40.42
Cyclin-Dependent Kinase-Like 5 Deficiency Disorder
G40.42 (also written G4042) is a billable ICD-10-CM diagnosis code for cyclin-Dependent Kinase-Like 5 Deficiency Disorder. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 58 codes in category G40 (Epilepsy and recurrent seizures). The Alphabetic Index lists it under 2 entries. Its coding notes include a Use additional code instruction, 5 Excludes1 entries and 12 Excludes2 entries.
Use additional code
Add the listed code as a secondary code, if known.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (8 notes)
- 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)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the Neuro Rehabilitation clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026Inclusion terms
Conditions classified to this code.
- CDKL5
Notes
- the following terms are to be considered equivalent to intractable: pharmacoresistant (pharmacologically resistant), treatment resistant, refractory (medically) and poorly controlled
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 2 entries