2027 ICD-10-CM Diagnosis Code Q02Microcephaly

ICD-10-CM Codes›Q00-Q99›Q00-Q07›Q02

ICD-10-CM Q02
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Q02 is a billable ICD-10-CM diagnosis code for microcephaly. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 91 through 93, 791, 793. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nervous system congenital anomalies.

For Medicare Advantage risk adjustment, Q02 maps to CMS-HCC Category 182 (Spinal Cord Disorders/Injuries) under the V28 model, adding a risk factor of about 0.478 for a community, non-dual, aged beneficiary in payment year 2027.

Code Identity

ICD-10-CM Code
Q02
Billable Status
Yes — Valid for Submission
Code Describes
Microcephaly
Short Description
Microcephaly
Same as the full description in the CMS dataset.
Chapter
Q00-Q07
Congenital malformations of the nervous system

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ00-Q07Congenital malformations of the nervous system
CategoryQ02Microcephaly
This CodeQ02Microcephaly

Present on Admission (POA)Billing

Q02 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Congenital malformations of the nervous system (Q00-Q07).

Medicare Risk Adjustment (HCC)Billing

Q02 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.

CMS-HCC V28 Category (Payment Model)
HCC 182— Spinal Cord Disorders/Injuries
Payment HCC · PY 2027 one of 251 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+0.478
community, non-dual, aged · ranges 0.270–0.478 across segments
Hierarchy
Superseded by HCC 180, HCC 181, HCC 191, and HCC 192
a more severe related category takes the payment when both are reported
Prior Model (CMS-HCC V24)
HCC 72
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 72 · ESRD (V21): HCC 72 · ESRD (V24): HCC 72
ESRD V21 weights: 0.102 dialysis, 0.256–0.456 functioning graft · ESRD V24 weights: 0.099 dialysis, 0.222–0.523 functioning graft
Part D (RxHCC)
RxHCC 155 — Spinal Cord Disorders
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Achalasia microcephaly syndrome
  • Achalasia of esophagus
  • Agammaglobulinemia, microcephaly, craniosynostosis, severe dermatitis syndrome
  • Amish lethal microcephaly
  • Anonychia
  • Anonychia with microcephaly syndrome
  • Aphalangy and syndactyly with microcephaly syndrome
  • Athetoid cerebral palsy
  • Atrophy of cerebellar vermis
  • Autosomal dominant primary microcephaly
  • Autosomal recessive chorioretinopathy and microcephaly syndrome
  • Autosomal recessive primary microcephaly
  • Bilateral congenital cataract of eyes
  • Brachycephaly
  • CIMDAG syndrome
  • Cleft palate, large ears, small head syndrome
  • Colobomatous microphthalmia
  • Congenital achalasia of esophagus
  • Congenital atrophy of optic nerve
  • Congenital conduction defect
  • Congenital hypoplasia of brain
  • Congenital ichthyosis, microcephalus, tetraplegia syndrome
  • Congenital intrauterine infection-like syndrome
  • Congenital kyphoscoliosis
  • Congenital kyphosis
  • Congenital microcephaly
  • Congenital microcephaly, severe encephalopathy, progressive cerebral atrophy syndrome
  • Congenital microencephaly
  • Congenital nephritis
  • Congenital porencephaly
  • Congenital prognathism
  • Congenital radioulnar synostosis
  • Congenital scoliosis deformity of spine
  • Cortical blindness
  • Diffuse atrophy of cerebellum
  • Diffuse atrophy of cerebrum
  • Diffuse cerebral and cerebellar atrophy, intractable seizures, progressive microcephaly syndrome
  • Disorder of cholesterol metabolism
  • Disorder of cholesterol synthesis
  • Disorder of serine metabolism
  • DONSON-related microcephaly, short stature, limb abnormalities spectrum
  • Dyskinetic cerebral palsy
  • Early-onset progressive diffuse brain atrophy, microcephaly, muscle weakness, optic atrophy syndrome
  • Epilepsy, microcephaly, skeletal dysplasia syndrome
  • Epiphyseal dysplasia, microcephalus, nystagmus syndrome
  • Extrasystoles, short stature, hyperpigmentation, microcephaly syndrome
  • Feingold syndrome
  • Fetal malformation of central nervous system
  • Fetal microcephaly
  • Galloway Mowat syndrome
  • Global brain atrophy
  • Global developmental delay, intellectual disability, microcephaly, short stature, brain iron accumulation syndrome
  • Goldberg Shprintzen megacolon syndrome
  • Hadziselimovic syndrome
  • Hydranencephaly
  • Hydromicrocephaly
  • Hypernatremia
  • Hypogonadotropic hypogonadism, severe microcephaly, sensorineural hearing loss, dysmorphism syndrome
  • Hypomyelination of central nervous system structure
  • Inborn error of amino acid metabolism
  • Inborn error of lipoprotein metabolism
  • Infantile cerebral and cerebellar atrophy with postnatal progressive microcephaly
  • Inherited disorder of folate metabolism
  • Insulin resistance
  • Intellectual disability, early-onset cataract, microcephaly syndrome
  • Intellectual disability, feeding difficulties, developmental delay, microcephaly syndrome
  • Kawashima Tsuji syndrome
  • MacDermot Winter syndrome
  • Macrotia
  • Malabsorption of glucose
  • Mandibulofacial dysostosis with microcephaly
  • Marfanoid physique
  • MECP2 related disorder
  • MEHMO syndrome
  • Microcephalic cortical malformations, short stature due to RTTN deficiency
  • Microcephalic osteodysplastic dysplasia Saul Wilson type
  • Microcephalic osteodysplastic primordial dwarfism type II
  • Microcephalic osteodysplastic primordial dwarfism types I and III
  • Microcephalic primordial dwarfism Alazami type
  • Microcephalic primordial dwarfism Dauber type
  • Microcephalic primordial dwarfism due to ZNF335 deficiency
  • Microcephalic primordial dwarfism Montreal type
  • Microcephalic primordial dwarfism Toriello type
  • Microcephalic primordial dwarfism, insulin resistance syndrome
  • Microcephalus cardiomyopathy syndrome
  • Microcephalus cleft palate syndrome
  • Microcephalus with albinism and digital anomaly syndrome
  • Microcephalus with brachydactyly and kyphoscoliosis syndrome
  • Microcephalus with cardiac defect and lung malsegmentation syndrome
  • Microcephalus, brain defect, spasticity, hypernatremia syndrome
  • Microcephalus, cerebellar hypoplasia, cardiac conduction defect syndrome
  • Microcephalus, complex motor and sensory axonal neuropathy syndrome
  • Microcephalus, glomerulonephritis, marfanoid habitus syndrome
  • Microcephalus, hypergonadotropic hypogonadism, short stature syndrome
  • Microcephalus, lymphedema, chorioretinopathy syndrome
  • Microcephaly
  • Microcephaly with cervical spine fusion anomaly
  • Microcephaly with simplified gyral pattern
  • Microcephaly, congenital cataract, psoriasiform dermatitis syndrome
  • Microcephaly, corpus callosum and cerebellar vermis hypoplasia, facial dysmorphism, intellectual disability syndrome
  • Microcephaly, corpus callosum hypoplasia, intellectual disability, facial dysmorphism syndrome
  • Microcephaly, facial dysmorphism, ocular anomalies, multiple congenital anomalies syndrome
  • Microcephaly, hypogammaglobulinemia, abnormal immunity syndrome
  • Microcephaly, intellectual disability, sensorineural hearing loss, epilepsy, abnormal muscle tone syndrome
  • Microcephaly, normal intelligence and immunodeficiency
  • Microcephaly, polymicrogyria, corpus callosum agenesis syndrome
  • Microcephaly, seizure, intellectual disability, heart disease syndrome
  • Microcephaly, short stature, intellectual disability, facial dysmorphism syndrome
  • Microcephaly, thin corpus callosum, intellectual disability syndrome
  • Microcephaly-capillary malformation syndrome
  • Microcornea
  • Microlissencephaly
  • Mild intellectual disability
  • Mild microcephaly
  • MMEP syndrome
  • Mowat-Wilson syndrome
  • MTHFS-related developmental delay, microcephaly, short stature, epilepsy syndrome
  • NDE1-related microhydranencephaly
  • Neonatal diabetes mellitus
  • Neonatal encephalopathy
  • Nijmegen breakage syndrome-like disorder
  • Non-spastic cerebral palsy
  • Osteodysplastic primordial dwarfism
  • Osteogenesis imperfecta, perinatal lethal
  • Osteogenesis imperfecta, recessive perinatal lethal, with microcephaly AND cataracts
  • Osteoplastic dysplasia
  • Permanent neonatal diabetes mellitus
  • Porencephaly, microcephaly, bilateral congenital cataract syndrome
  • Postnatal microcephaly, infantile hypotonia, spastic diplegia, dysarthria, intellectual disability syndrome
  • Primary microcephaly, epilepsy, permanent neonatal diabetes syndrome
  • Primary microcephaly, mild intellectual disability, young-onset diabetes syndrome
  • Progressive microcephaly
  • Progressive microcephaly, seizures, cortical blindness, developmental delay syndrome
  • Progressive microcephaly, seizures, cortical blindness, developmental delay with combined immunodeficiency due to DIAPH1 mutation
  • Psoriasiform dermatitis
  • PYCR2-related microcephaly, progressive leukoencephalopathy
  • Radioulnar synostosis with microcephaly and scoliosis syndrome
  • Second cranial nerve finding
  • Secondary microcephaly
  • Seemanova Lesny syndrome
  • SETD2-related microcephaly, severe intellectual disability, multiple congenital anomalies syndrome
  • Severe combined immunodeficiency with low T- and B-cell numbers
  • Severe combined immunodeficiency, microcephaly, growth retardation, sensitivity to ionizing radiation syndrome
  • Severe feeding difficulties, failure to thrive, microcephaly due to ASXL3 deficiency syndrome
  • Severe global developmental delay
  • Severe intellectual disability, progressive postnatal microcephaly, midline stereotypic hand movements syndrome
  • Severe microbrachycephaly, intellectual disability, athetoid cerebral palsy syndrome
  • Severe neonatal onset encephalopathy with microcephaly
  • Severe X-linked intellectual disability Gustavson type
  • Spastic tetraplegia
  • Spastic tetraplegia, thin corpus callosum, progressive postnatal microcephaly syndrome
  • Sporadic fetal brain disruption sequence
  • Steroid-resistant nephrotic syndrome
  • THOC6-related developmental delay-microcephaly-facial dysmorphism syndrome
  • USP18 deficiency
  • X-linked colobomatous microphthalmia, microcephaly, intellectual disability, short stature syndrome
  • X-linked microcephaly, growth retardation, prognathism, cryptorchidism syndrome

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Q02: its own notes plus those printed at Chapter 17. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

  • hydromicrocephaly
  • micrencephalon

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

  • Meckel-Gruber syndrome (Q61.9)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 17 (Q00-QA1) Congenital malformations, deformations and chromosomal abnormalities applies to 900 codes
  • inborn errors of metabolism (E70-E88)

Code First

The underlying condition named in the note is sequenced before this code.

  • if applicable, congenital Zika virus disease

Notes

General instructions on how these codes are used.

From Chapter 17 (Q00-QA1) Congenital malformations, deformations and chromosomal abnormalities applies to 900 codes
  • Codes from this chapter are not for use on maternal records

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name Q02, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming Q02: they are not reported together with it, unless the two conditions are unrelated.

  • Q75 Other congenital malformations of skull and face bones
    microcephaly (Q02)

Use Additional Code 1

These codes say to use an additional code from the note, and Q02 is one of the codes named.

  • Q87.88 CTNNB1 syndrome
    microcephaly (Q02)

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

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

  • Microcephaly

    a congenital abnormality in which the cerebrum is underdeveloped, the fontanels close prematurely, and, as a result, the head is small. (desk reference for neuroscience, 2nd ed.)

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 Q02 to ICD-9-CMHistory

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

ICD-9-CM
742.1 Microcephalus
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Q02Overview

What is the ICD-10 code for microcephaly?

The ICD-10-CM code for microcephaly is Q02. It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is Q02 (Microcephaly) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report microcephaly on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does Q02 group to?

When microcephaly is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, 91, 92, 93, with relative weights from 0.7783 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.

Is Q02 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 microcephaly on inpatient claims. The code appears in the Congenital malformations of the nervous system (Q00-Q07) range of the CMS exempt list.

Can Q02 be reported with Q61.9?

Not as a rule. The Excludes1 note on Q02 lists "Meckel-Gruber syndrome (Q61.9)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What HCC is Q02?

Q02 (microcephaly) maps to CMS-HCC Category 182 (Spinal Cord Disorders/Injuries), commonly written as HCC 182, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 72 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 155.

Does Q02 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, Q02 adds a risk adjustment factor of about 0.478 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.270 to 0.478 depending on the payment segment). A more severe related category (HCC 180, HCC 181, HCC 191, and HCC 192) supersedes it when both are reported. See the full factor table on the HCC 182 category page.