2026 ICD-10-CM Diagnosis Code Q04.8Other specified congenital malformations of brain

ICD-10-CM Codes›Q00-Q99›Q00-Q07›Q04

ICD-10-CM Q04.8
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Q04.8 is a billable ICD-10-CM diagnosis code for other specified congenital malformations of brain. 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
Q04.8
Billable Status
Yes — Valid for Submission
Code Describes
Other specified congenital malformations of brain
Short Description
Other specified congenital malformations of brain
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 CodeQ04.8Other specified congenital malformations of brain

Present on Admission (POA)Billing

Q04.8 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.

  • 3C syndrome
  • Abnormality of neurogenesis
  • Aprosencephaly
  • Aprosencephaly cerebellar dysgenesis
  • Aprosencephaly/atelencephaly spectrum
  • Athabaskan brainstem dysgenesis syndrome
  • CEDNIK syndrome
  • Central bilateral macrogyria
  • Cerebellar cortical dysplasia
  • Cerebellar hemangioblastomatosis
  • Cerebral ventriculomegaly, cystic kidney disease
  • Cerebro-facio-thoracic dysplasia
  • Chiari malformation
  • Chiari malformation type IV
  • Coffin-Siris syndrome
  • Colpocephaly
  • Communicating hydrocephalus co-occurrent and due to congenital agenesis of arachnoid villi
  • Congenital abnormal shape of cerebellum
  • Congenital abnormal shape of cerebrum
  • Congenital aniridia
  • Congenital dysplasia of fronto-parietal cortex
  • Congenital enlargement of ventricle of brain
  • Congenital intrauterine infection-like syndrome
  • Congenital malformation of the meninges
  • Congenital pseudobulbar palsy
  • Congenital sequelae of disorders
  • Congenital superior cerebellar dysplasia
  • Cortical dysplasia
  • Cortical dysplasia with hemimegalencephaly
  • Cystic malformation of posterior fossa
  • Dandy-Walker syndrome
  • Defect of telencephalic division
  • Dentate dysplasia
  • Diencephalic mesencephalic junction dysplasia
  • Ecchordosis physaliphora
  • Ectopic glial tissue
  • Ectopic gray matter
  • Ectopic gray matter in centrum ovale
  • Exencephaly
  • Focal cortical dysplasia Blumcke type III
  • Focal cortical dysplasia Blumcke type IIIa
  • Focal cortical dysplasia type I
  • Focal cortical dysplasia type Ia
  • Focal cortical dysplasia type Ib
  • Focal cortical dysplasia type II
  • Focal cortical dysplasia type IIa
  • Focal cortical dysplasia type IIb
  • Gelastic seizures with hypothalamic hamartoma
  • Gillespie syndrome
  • Hamartoma of brain
  • Hamartoma of hypothalamus
  • Infantile hemangioma
  • Isolated focal cortical dysplasia
  • Laminar heterotopia
  • Localized cortical dysplasia
  • Macrogyria
  • MECP2 related disorder
  • Microdysgenesis
  • Nasal glial heterotopia
  • Neuronal heterotopia
  • Nodular heterotopia
  • Olivary heterotopia
  • Olive dysplasia
  • Periventricular nodular heterotopia
  • Pettigrew syndrome
  • PHACE syndrome
  • Posterior-predominant lissencephaly, broad flat pons and medulla-midline crossing defects syndrome
  • PPM-X syndrome
  • Pseudobulbar palsy
  • Subcortical nodular heterotopia
  • Subependymal nodular heterotopia
  • Tubulinopathy-associated dysgyria
  • Type 1 lissencephaly
  • Ulegyria
  • Upper motor neuron disease
  • Ventriculomegaly
  • Ventriculomegaly due to developmental anomaly

Tabular List NotesGuidance

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

Inclusion Terms

  • Arnold-Chiari syndrome, type IV
  • Macrogyria

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.

    • Anomaly, anomalous(congenital) (unspecified type)
      • meninges
        • cerebral
    • Arnold-Chiari disease, obstruction or syndrome(type II)
      • type IV
    • Deformity
      • meninges or membrane (congenital)
        • cerebral
    • Dilatation
      • ventricular, ventricle (acute) (chronic)
        • cerebral, congenital
    • Displacement, displaced
      • brain stem, caudal (congenital)
    • Displacement, displaced
      • cerebellum, caudal (congenital)
    • Distortion(s) (congenital)
      • gyri
    • Ectopic, ectopia(congenital)
      • brain
    • Ectopic, ectopia(congenital)
      • cerebral
    • Heterotopia, heterotopic
      • cerebralis
    • Macrogyria(congenital)
    • Malformation(congenital)
      • brain (multiple)
        • specified type NEC
    • Malformation(congenital)
      • meninges or membrane (congenital)
        • cerebral
    • Malposition
      • congenital
        • brain tissue
    • Softening
      • brain (necrotic) (progressive)
        • congenital
    • Ulegyria

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

  • Pseudobulbar Palsy

    a syndrome characterized by dysarthria, dysphagia, dysphonia, impairment of voluntary movements of tongue and facial muscles, and emotional lability. this condition is caused by diseases that affect the motor fibers that travel from the cerebral cortex to the lower brain stem (i.e., corticobulbar tracts); including multiple sclerosis; motor neuron disease; and cerebrovascular disorders. (from adams et al., principles of neurology, 6th ed, p489)

  • Periventricular Nodular Heterotopia

    a disorder resulting from a defect in the pattern of neuronal migration in which ectopic collections of neurons lie along the lateral ventricles of the brain or just beneath, contiguously or in isolated patches.

  • ACD Gene Mutation|ACD, Shelterin Complex Subunit and Telomerase Recruitment Factor Gene Mutation|Adrenocortical Dysplasia Homolog (Mouse) Gene Mutation|PIP1 Gene Mutation|PTOP Gene Mutation|TINT1 Gene Mutation|TPP1 Gene Mutation

    a change in the nucleotide sequence of the acd gene.

  • ACD wt Allele|ACD, Mouse, Homolog of Gene|ACD, Shelterin Complex Subunit and Telomerase Recruitment Factor wt Allele|Adrenocortical Dysplasia Homolog (Mouse) Gene|PIP1|PTOP|TPP1

    human acd wild-type allele is located in the vicinity of 16q22.1 and is approximately 3 kb in length. this allele, which encodes adrenocortical dysplasia protein homolog, is involved in telomere protection.

  • Adrenocortical Dysplasia Protein Homolog|ACD|POT1 and TIN2 Organizing Protein|POT1 and TIN2-Interacting Protein|POT1- and TIN2- Organizing Protein|POT1-Interacting Protein 1|TIN2 Interacting Protein 1|TIN2-Interacting Protein 1|Telomere Protein TPP1

    adrenocortical dysplasia protein homolog (544 aa, ~58 kda) is encoded by the human acd gene. this protein plays a role in both the elongation and maintenance of telomeres.

  • Complex Cortical Dysplasia with other Brain Malformations 5|CDCBM5|TUBB2A Tubulinopathy

    an autosomal dominant condition caused by mutation(s) in the tubb2a gene, encoding tubulin beta-2a chain. it is characterized by cortical dysplasia and is associated with impaired intellectual development, hypotonia, global developmental delay, cortical dysplasia, and dysmorphic corpus callosum.

  • Cortical Dysplasia

    malformation of the cerebral cortex due to improper migration of neurons in utero.

  • Cortical Dysplasia-Focal Epilepsy Syndrome|CDFE Syndrome

    an autosomal recessive condition caused by mutation(s) in the cntnap2 gene, encoding contactin-associated protein-like 2. it is characterized by normal development until the onset of intractable focal seizures at age 1-9. after the onset of seizures, language regression, intellectual disability, hyperactivity, and impulsive behaviors begin to occur. the majority of children eventually fulfill the criteria for autism spectrum disorder.

  • Aprosencephaly

    a very rare congenital brain defect in which the cerebral cortex, striatum, globus pallidus, thalamus, hypothalamus, and eyes are absent or rudimentary.

  • Ecchordosis Physaliphora

    a very rare, slow growing, usually asymptomatic hamartomatous lesion that arises from ectopic notochordal tissue. morphologically it is characterized by the presence of typical physaliphorous cells in a myxoid background.

  • Pseudobulbar Palsy

    a condition affecting cranial nerves ix-xii resulting from upper motor neuron damage arising from a variety of causes.

  • Focal Cortical Dysplasia Type 1|FCD1|FCDI|Focal Cortical Dysplasia Type I

    focal cortical dysplasia characterized by abnormal cortical layering. it is associated with mild symptoms, late onset, and changes present in the temporal lobe. it includes the following: type ia with abnormal radial migration and maturation of neurons; type ib with disruption of the six-layered tangential composition of the cortex with immature neurons; and type ic comprising both architectural abnormalities.

  • Focal Cortical Dysplasia Type 2|FCD2|FCDII|Focal Cortical Dysplasia Type II

    focal cortical dysplasia characterized by disrupted cortical lamination and specific cytological abnormalities. it includes type iia with dysmorphic neurons and type iib with dysmorphic neurons and balloon cells.

  • Focal Cortical Dysplasia Type 3|FCD3|FCDIII|Focal Cortical Dysplasia Type III

    focal cortical dysplasia characterized by different cortical dyslamination and cytological abnormalities with the main lesions located in the same area. it includes the following: type iiia with architectural distortion of cortical layer in temporal lobe with hippocampal atrophy; type iiib with architectural distortion of cortical layer adjacent to glial or glioneuronal tumor; type iiic with architectural distortion of cortical layer adjacent to vascular malformation; and type iiid with architectural distortion of cortical layer adjacent to other lesions acquired in early childhood (e.g., trauma, ischemic event, and encephalitis).

  • Focal Cortical Dysplasia|FCD

    a congenital cortical developmental abnormality characterized by focal architectural distortion of the cortical brain layers. it is associated with the presence of cytologic abnormalities including hypertrophic and dysmorphic neurons. it is caused by genetic or acquired factors and is often associated with epilepsy.

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 Q04.8 to ICD-9-CMHistory

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

ICD-9-CM
742.4 Brain anomaly NEC
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 Q04.8Overview

Is Q04.8 (Other congenital malformations of brain) a billable code?

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

Is Q04.8 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 other specified congenital malformations of brain on inpatient claims.

What is the ICD-9 equivalent of Q04.8?

Under the General Equivalence Mappings, other specified congenital malformations of brain converts to ICD-9-CM 742.4 (brain anomaly NEC). 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.