Q04.3

Billable
ChapterQ00–Q99
Ranksubcategory
Official Description

Other reduction deformities of brain

Metadata & Insights
  • •2026 ICD-10-CM Edition - Effective October 1, 2025.
  • •Billable/specific code (valid for reimbursement).
  • •Chapter 17: Congenital Malformations, Deformations and Chromosomal Abnormalities (Q00-Q99).

Instructional Notes

Includes
  • Absence of part of brain
  • Agenesis of part of brain
  • Agyria
  • Aplasia of part of brain
  • Hydranencephaly
  • Hypoplasia of part of brain
  • Lissencephaly
  • Microgyria
  • Pachygyria
Excludes1(Not coded here)
  • congenital malformations of corpus callosum (Q04.0)
General instructions are available for the parent sections:
View CH17 NotesView Q04 Notes

Clinical Hierarchy

CH17Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0)
Q00-Q07Congenital malformations of the nervous system (Q00-Q07)
Q04Other congenital malformations of brain
Q04.3Other reduction deformities of brain

Applicable Ancestor Context

The following parent sections contain instructions or notes that apply to Q04.3:

categoryQ04
Other congenital malformations of brain
View context instructions
chapterCH17
Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0)
View context instructions

Alphabetic Index Mentions

These are Diagnosis Index lookup paths that route to Q04.3. Use them as entry terms for search, then confirm final coding instructions in the Tabular List and notes above.

18 raw paths
Absence (of) (organ or part) (complete or partial)2 unique routes
brain
part of→Q04.3
cerebellum (vermis)→Q04.3
Agenesis3 unique routes
brain
part of→Q04.3
cerebellum→Q04.3
vermis of cerebellum→Q04.3
Agyria1 unique routes
Direct index entry→Q04.3
Aplasia2 unique routes
brain
part of→Q04.3
cerebellum→Q04.3
Deformity2 unique routes
brain (congenital)
reduction→Q04.3
reduction (extremity) (limb), congenital
brain→Q04.3
Hydrancephaly, hydranencephaly1 unique routes
Direct index entry→Q04.3
Hypoplasia, hypoplastic3 unique routes
brain(2 variants)
gyri→Q04.3
part of→Q04.3
cerebellum→Q04.3
Lissencephalia, lissencephaly1 unique routes
Direct index entry→Q04.3
Microgyria (congenital)1 unique routes
Direct index entry→Q04.3
Nondevelopment1 unique routes
brain
part of→Q04.3
Pachygyria1 unique routes
Direct index entry→Q04.3

MS-DRG Classification

2026 v43.1

This code is grouped within the following Diagnosis Related Group(s) for clinical reimbursement:

DRG 091
Other Disorders of Nervous System with MCC
DRG 092
Other Disorders of Nervous System with CC
DRG 093
Other Disorders of Nervous System without CC/MCC
DRG 791
Prematurity with Major Problems
DRG 793
Full Term Neonate with Major Problems

Cross Reference

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