ICD-10-CM 2027
ICD-10 code for Cyclencephaly
From the official ICD-10-CM alphabetic index entry “Cyclencephaly”. Page updated September 29, 2026.
About coding Cyclencephaly
The ICD-10-CM code for Cyclencephaly is Q04.9 (Congenital malformation of brain, unspecified).
Within Q04, choose Q04.9 (Congenital malformation of brain, unspecified) only when documentation doesn't support a more specific option: congenital malformations of corpus callosum (Q04.0), Arhinencephaly (Q04.1), holoprosencephaly (Q04.2), other reduction deformities of brain (Q04.3), Septo-optic dysplasia of brain (Q04.4), Megalencephaly (Q04.5), congenital cerebral cysts (Q04.6) and other specified congenital malformations of brain (Q04.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 091 (Other Disorders of Nervous System with MCC, relative weight 1.7046), DRG 092 (Other Disorders of Nervous System with CC, relative weight 1.0239), DRG 093 (Other Disorders of Nervous System without CC/MCC, relative weight 0.7783), DRG 791 (Prematurity with Major Problems, relative weight 4.1075) and DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), in MDC 01 (Diseases and Disorders of the Nervous System) and MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about Cyclencephaly ICD-10 codes
What is the ICD-10 code for Cyclencephaly?
- Q04.9 — Congenital malformation of brain, unspecified.
Is Q04.9 billable?
- Yes. Q04.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Q04.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Q04.9 as a principal diagnosis.
Is Q04.9 a CC or MCC?
- No. Q04.9 is neither a CC nor an MCC under MS-DRG v44.0.