ICD-10-CM 2027
ICD-10 code for trisomy syndrome
From the official ICD-10-CM alphabetic index entry “Syndrome › trisomy”. Page updated September 29, 2026.
About coding trisomy syndrome
The ICD-10-CM code for trisomy syndrome is Q92.9 (Trisomy and partial trisomy of autosomes, unspecified). The official index lists 17 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on Q92.9.
Within Q92, choose Q92.9 (Trisomy and partial trisomy of autosomes, unspecified) only when documentation doesn't support a more specific option: whole chromosome trisomy, nonmosaicism (meiotic nondisjunction) (Q92.0), whole chromosome trisomy, mosaicism (mitotic nondisjunction) (Q92.1), partial trisomy (Q92.2), Duplications with other complex rearrangements (Q92.5), marker chromosomes (Q92.6), Triploidy and polyploidy (Q92.7) and other specified trisomies and partial trisomies of autosomes (Q92.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 951 (Other Factors Influencing Health Status, relative weight 0.5577), in MDC 23 (Factors Influencing Health Status and Other Contacts with Health Services), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific trisomy syndrome codes (official index)
- 13 Q91.7 — Trisomy 13, unspecified
- meiotic nondisjunction Q91.4 — Trisomy 13, nonmosaicism (meiotic nondisjunction)
- mitotic nondisjunction Q91.5 — Trisomy 13, mosaicism (mitotic nondisjunction)
- mosaicism Q91.5 — Trisomy 13, mosaicism (mitotic nondisjunction)
- translocation Q91.6 — Trisomy 13, translocation
- 18 Q91.3 — Trisomy 18, unspecified
- meiotic nondisjunction Q91.0 — Trisomy 18, nonmosaicism (meiotic nondisjunction)
- mitotic nondisjunction Q91.1 — Trisomy 18, mosaicism (mitotic nondisjunction)
- mosaicism Q91.1 — Trisomy 18, mosaicism (mitotic nondisjunction)
- translocation Q91.2 — Trisomy 18, translocation
- 20 (q)(p) Q92.8 — Other specified trisomies and partial trisomies of autosomes
- 21 Q90.9 — Down syndrome, unspecified
- meiotic nondisjunction Q90.0 — Trisomy 21, nonmosaicism (meiotic nondisjunction)
- mitotic nondisjunction Q90.1 — Trisomy 21, mosaicism (mitotic nondisjunction)
- mosaicism Q90.1 — Trisomy 21, mosaicism (mitotic nondisjunction)
- translocation Q90.2 — Trisomy 21, translocation
- 22 Q92.8 — Other specified trisomies and partial trisomies of autosomes
Common questions about trisomy syndrome ICD-10 codes
What is the ICD-10 code for trisomy syndrome?
- Q92.9 — Trisomy and partial trisomy of autosomes, unspecified. More specific codes apply when the documentation supports them: Q91.7, Q91.4, Q91.5, Q91.5 and others below.
What is the ICD-10 code for 13 trisomy syndrome?
- Q91.7 — Trisomy 13, unspecified.
What is the ICD-10 code for 18 trisomy syndrome?
- Q91.3 — Trisomy 18, unspecified.
What is the ICD-10 code for 20 trisomy syndrome?
- Q92.8 — Other specified trisomies and partial trisomies of autosomes.
What is the ICD-10 code for 21 trisomy syndrome?
- Q90.9 — Down syndrome, unspecified.
What is the ICD-10 code for 22 trisomy syndrome?
- Q92.8 — Other specified trisomies and partial trisomies of autosomes.
Is Q92.9 billable?
- Yes. Q92.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Q92.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Q92.9 as a principal diagnosis.
Is Q92.9 a CC or MCC?
- No. Q92.9 is neither a CC nor an MCC under MS-DRG v44.0.