2026 ICD-10-CM Diagnosis Code Q90Down syndrome

ICD-10-CM Codes›Q00-Q99›Q90-Q99›Q90

ICD-10-CM Q90
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Q90 is a non-billable ICD-10-CM category code for down syndrome, so it cannot be submitted on claims. Use a more specific code from this category instead, such as Q90.0, Q90.1, Q90.2, and Q90.9.

Code Identity

ICD-10-CM Code
Q90
Billable Status
No — Non-Billable Category
Code Describes
Down syndrome
Chapter
Q90-Q99
Chromosomal abnormalities, not elsewhere classified

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ90-Q99Chromosomal abnormalities, not elsewhere classified
CategoryQ90Down syndrome
This CodeQ90Down syndrome

Specific Coding for Down syndromeOverview

Non-specific codes like Q90 require more characters. Use one of these billable codes instead:

  • Use Q90.0 for Trisomy 21, nonmosaicism (meiotic nondisjunction)

  • Use Q90.1 for Trisomy 21, mosaicism (mitotic nondisjunction)

  • Use Q90.2 for Trisomy 21, translocation

  • Use Q90.9 for Down syndrome, unspecified

Tabular List NotesGuidance

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

Code Also

  • associated physical conditions, such as atrioventricular septal defect Q21.2

Use Additional Code

  • codes to identify any associated degree of intellectual disabilities F70 F79

Clinical InformationClinical

  • Down Syndrome

    a chromosome disorder associated either with an extra chromosome 21 or an effective trisomy for chromosome 21. clinical manifestations include hypotonia, short stature, brachycephaly, upslanting palpebral fissures, epicanthus, brushfield spots on the iris, protruding tongue, small ears, short, broad hands, fifth finger clinodactyly, single transverse palmar crease, and moderate to severe intellectual disability. cardiac and gastrointestinal malformations, a marked increase in the incidence of leukemia, and the early onset of alzheimer disease are also associated with this condition. pathologic features include the development of neurofibrillary tangles in neurons and the deposition of amyloid beta-protein, similar to the pathology of alzheimer disease. (menkes, textbook of child neurology, 5th ed, p213)

Patient EducationClinical

Down Syndrome

Down syndrome is a condition in which a person has an extra chromosome or an extra piece of a chromosome. This extra copy changes how a baby's body and brain develop. It can cause both mental and physical challenges during their lifetime.

The full article covers:

  • What is Down syndrome?
  • What causes Down syndrome?
  • What are the symptoms of Down syndrome?
  • What other problems does Down syndrome cause?
  • How is Down syndrome diagnosed?
  • What are the treatments for Down syndrome?

Read the full article at MedlinePlus

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

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 Q90Overview

Is Q90 (Down syndrome) a billable code?

No. This is a category header that groups the codes for down syndrome, and headers cannot be submitted on claims. Claims for down syndrome need a more specific code from this category, such as Q90.0, Q90.1, and Q90.2.