Q92.1
Whole chromosome trisomy, mosaicism (mitotic nondisjunction)
Q92.1 (also written Q921) is a billable ICD-10-CM diagnosis code for whole chromosome trisomy, mosaicism (mitotic nondisjunction). It is part of the FY2027 code set, effective October 1, 2026. It is one of the 9 codes in category Q92 (Other trisomies and partial trisomies of the autosomes, not elsewhere classified). The Alphabetic Index lists it under 4 entries. Its coding notes include 1 Excludes1 entry and 2 Excludes2 entries.
Guidelines tip
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
Chapter 17 codes can be used for life. Manifestations that are an inherent part of a specifically coded anomaly are not coded separately. A corrected malformation is reported with a personal history code.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
- trisomies of chromosomes 13, 18, 21 (Q90-Q91)
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (2 notes)
- mitochondrial metabolic disorders (E88.4-)
- inborn errors of metabolism (E70-E88)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Other clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026Includes
Further defines or gives examples of the content of the category.
- unbalanced translocations and insertions
Notes
Also from chapter/block level (1 note)
- Codes from this chapter are not for use on maternal records
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 4 entries