NPI Atlas

Q90 – Down syndrome

ICD-10-CM 2027 diagnosis code · Chromosomal abnormalities, not elsewhere classified

Non-billable header

ICD-10-CM code Q90

Code: Q90 (claims format: Q90)
Description: Down syndrome
Billable: No – use a more specific code below
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 17. Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (Q00-QA1)
Block: Q90-Q99 Chromosomal abnormalities, not elsewhere classified

Billable codes under Q90

Q90 is a header code and cannot be used on claims. Choose the most specific code:

Q90.0 – Trisomy 21, nonmosaicism (meiotic nondisjunction)Billable
Q90.1 – Trisomy 21, mosaicism (mitotic nondisjunction)Billable
Q90.2 – Trisomy 21, translocationBillable
Q90.9 – Down syndrome, unspecifiedBillable

Notes for Q90

Use additional code:

code(s) to identify any associated degree of intellectual disabilities (F70-F79)

Code also:

associated physical condition(s), such as atrioventricular septal defect (Q21.2-)

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

Block Q90-Q99

Excludes2 (not included here):

mitochondrial metabolic disorders (E88.4-)

Frequently asked questions

What is ICD-10 code Q90?

Q90 is the ICD-10-CM code for down syndrome, in the block Q90-Q99 (Chromosomal abnormalities, not elsewhere classified).

Is Q90 a billable code?

No. Q90 is a header code with more specific child codes; report one of the billable codes listed above.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.