Q90 Down syndrome

Category / Non-billable header 4 subcodes

Block: Chromosomal abnormalities, not elsewhere classified (Q90-Q99)

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-)

Subcodes

Subcodes are listed below for reference. Detail pages are not available for chapters 11–22.

Code Description Billable
Q90..0 Trisomy 21, nonmosaicism (meiotic nondisjunction) Yes
Q90..1 Trisomy 21, mosaicism (mitotic nondisjunction) Yes
Q90..2 Trisomy 21, translocation Yes
Q90..9 Down syndrome, unspecified Yes

Last reviewed: September 2026