Q90: Down syndrome
Codes under Q90 (Down syndrome). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.
| Code | Description | Billable |
|---|---|---|
| Q90.0 | Trisomy 21, nonmosaicism (meiotic nondisjunction) | ✓ |
| Q90.0 | Trisomy 21, nonmosaicism (meiotic nondisjunction) | ✓ |
| Q90.1 | Trisomy 21, mosaicism (mitotic nondisjunction) | ✓ |
| Q90.1 | Trisomy 21, mosaicism (mitotic nondisjunction) | ✓ |
| Q90.2 | Trisomy 21, translocation | ✓ |
| Q90.2 | Trisomy 21, translocation | ✓ |
| Q90.9 | Down syndrome, unspecified | ✓ |
| Q90.9 | Down syndrome, unspecified | ✓ |
Frequently asked questions
What is ICD-10-CM code Q90?
Q90 is an ICD-10-CM category covering Down syndrome. It contains 8 more specific diagnosis codes, 8 of which are billable.
Is Q90 a billable code?
No — Q90 is a category header and isn't billable on its own. Code to the highest level of specificity using one of its subcodes (for example Q90.0 — Trisomy 21, nonmosaicism (meiotic nondisjunction)). 8 of the 8 codes under Q90 are billable.
What codes fall under Q90?
Q90 includes Q90.0, Q90.0, Q90.1, Q90.1, Q90.2, plus 3 more. See the full list with descriptions and billable status above.
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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.
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