2026 ICD-10-CM Diagnosis Code Q04.0Congenital malformations of corpus callosum

ICD-10-CM Codes›Q00-Q99›Q00-Q07›Q04

ICD-10-CM Q04.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Q04.0 is a billable ICD-10-CM diagnosis code for congenital malformations of corpus callosum. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nervous system congenital anomalies.

Code Identity

ICD-10-CM Code
Q04.0
Billable Status
Yes — Valid for Submission
Code Describes
Congenital malformations of corpus callosum
Short Description
Congenital malformations of corpus callosum
Same as the full description in the CMS dataset.
Parent Code
Q04
Other congenital malformations of brain

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ00-Q07Congenital malformations of the nervous system
CategoryQ04Other congenital malformations of brain
This CodeQ04.0Congenital malformations of corpus callosum

Present on Admission (POA)Billing

Q04.0 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acrocallosal syndrome
  • Agenesis of corpus callosum
  • Agenesis of corpus callosum and abnormal genitalia syndrome
  • Agenesis of corpus callosum with lipoma
  • Agenesis of corpus callosum, intellectual disability, coloboma, micrognathia syndrome
  • Agenesis of corpus callosum, macrocephaly, hypertelorism syndrome
  • Andermann syndrome
  • Aplasia of corpus callosum
  • Atrophy of corpus callosum
  • Congenital coloboma of iris
  • Congenital hypoplasia of cerebral hemisphere
  • Congenital hypoplasia of cerebral white matter
  • Congenital malformation of corpus callosum
  • Disorder of serine metabolism
  • Hypoplasia of corpus callosum
  • Infantile osteopetrosis with neuroaxonal dysplasia syndrome
  • Intellectual disability, hypoplastic corpus callosum, preauricular tag syndrome
  • L1 syndrome
  • Mass of preauricular region
  • Microcephaly, corpus callosum and cerebellar vermis hypoplasia, facial dysmorphism, intellectual disability syndrome
  • Microcephaly, corpus callosum hypoplasia, intellectual disability, facial dysmorphism syndrome
  • Microcephaly, polymicrogyria, corpus callosum agenesis syndrome
  • Microcephaly, thin corpus callosum, intellectual disability syndrome
  • Partial agenesis of corpus callosum
  • Partial corpus callosum agenesis, cerebellar vermis hypoplasia with posterior fossa cysts syndrome
  • Severe intellectual disability, agenesis of corpus callosum, facial dysmorphism, cerebellar ataxia syndrome
  • Spastic tetraplegia, thin corpus callosum, progressive postnatal microcephaly syndrome
  • Temtamy syndrome
  • White matter hypoplasia, corpus callosum agenesis, intellectual disability syndrome
  • X-linked complicated corpus callosum dysgenesis
  • X-linked lissencephaly with abnormal genitalia syndrome

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Agenesis of corpus callosum

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Absence(of) (organ or part) (complete or partial)
      • corpus callosum
    • Agenesis
      • corpus callosum
    • Aplasia
      • corpus callosum
    • Hypoplasia, hypoplastic
      • corpus callosum
    • Malformation(congenital)
      • corpus callosum (congenital)

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MAL004
Nervous system congenital anomalies
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Agenesis of Corpus Callosum

    birth defect that results in a partial or complete absence of the corpus callosum. it may be isolated or a part of a syndrome (e.g., aicardi's syndrome; acrocallosal syndrome; andermann syndrome; and holoprosencephaly). clinical manifestations include neuromotor skill impairment and intellectual disability of variable severity.

  • Aicardi Syndrome

    a rare genetic disorder characterized by partial or complete absence of the corpus callosum, resulting in infantile spasms, mental retardation, and lesions of the retina or optic nerve.

  • Acrocallosal Syndrome

    autosomal recessive syndrome characterized by hypogenesis or agenesis of corpus callosum. clinical features include mental retardation; craniofacial abnormalities; digital malformations, and growth retardation.

  • Acrocallosal Syndrome

    a rare genetic syndrome characterized by agenesis of the corpus callosum, polydactyly, mental and motor retardation.

Patient EducationClinical

Brain Malformations

Most brain malformations begin long before a baby is born. Something damages the developing nervous system or causes it to develop abnormally. Sometimes it's a genetic problem. In other cases, exposure to certain medicines, infections, or radiation during pregnancy interferes with brain development.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert Q04.0 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
742.2 Reduction deform, brain
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About Q04.0Overview

Is Q04.0 (Other congenital malformations of brain) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report congenital malformations of corpus callosum on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is Q04.0 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for congenital malformations of corpus callosum on inpatient claims.

What is the ICD-9 equivalent of Q04.0?

Under the General Equivalence Mappings, congenital malformations of corpus callosum converts to ICD-9-CM 742.2 (reduction deform, brain). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.