2027 ICD-10-CM Diagnosis Code Q92.1Whole chromosome trisomy, mosaicism (mitotic nondisjunction)

ICD-10-CM Codes›Q00-Q99›Q90-Q99›Q92

ICD-10-CM Q92.1
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Q92.1 is a billable ICD-10-CM diagnosis code for whole chromosome trisomy, mosaicism (mitotic nondisjunction). It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 951. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Chromosomal abnormalities.

Q92.1 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 148 for payment year 2027.

Code Identity

ICD-10-CM Code
Q92.1
Billable Status
Yes — Valid for Submission
Code Describes
Whole chromosome trisomy, mosaicism (mitotic nondisjunction)
Short Description
Whole chromosome trisomy, mosaicism (mitotic nondisjunction)
Same as the full description in the CMS dataset.
Parent Code
Q92
Other trisomies and partial trisomies of the autosomes, not elsewhere classified

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ90-Q99Chromosomal abnormalities, not elsewhere classified
CategoryQ92Other trisomies and partial trisomies of the autosomes, not elsewhere classified
This CodeQ92.1Whole chromosome trisomy, mosaicism (mitotic nondisjunction)

Present on Admission (POA)Billing

Q92.1 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Chromosomal abnormalities, not elsewhere classified (Q90-Q99).

Medicare Risk Adjustment (HCC)Billing

Q92.1 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model, but it maps to payment categories in the other CMS models shown below.

CMS-HCC V28 (Medicare Advantage Payment Model)
Not mapped
no payment category in the model that pays 100% of MA risk scores
Prior Model (CMS-HCC V24)
Not mapped under V24
this diagnosis newly risk-adjusts under the V28 model
Part D (RxHCC)
RxHCC 148 — Mild or Unspecified Intellectual Disability/Developmental Disorder
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Mosaic trisomy 1 syndrome
  • Mosaic trisomy 10 syndrome
  • Mosaic trisomy 12 syndrome
  • Mosaic trisomy 14 syndrome
  • Mosaic trisomy 15 syndrome
  • Mosaic trisomy 16 syndrome
  • Mosaic trisomy 17 syndrome
  • Mosaic trisomy 2 syndrome
  • Mosaic trisomy 20 syndrome
  • Mosaic trisomy 22 syndrome
  • Mosaic trisomy 3 syndrome
  • Mosaic trisomy 4 syndrome
  • Mosaic trisomy 5 syndrome
  • Mosaic trisomy 7 syndrome
  • Mosaic trisomy 9 syndrome
  • Trisomy 10
  • Trisomy 12
  • Trisomy 22
  • Whole chromosome trisomy - mitotic nondisjunction mosaicism
  • Whole chromosome trisomy, mosaicism

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Q92.1: its own notes plus those printed at Q92, block Q90-Q99, and Chapter 17. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Q92 Other trisomies and partial trisomies of the autosomes, not elsewhere classified applies to 9 codes
  • unbalanced translocations and insertions

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Q92 Other trisomies and partial trisomies of the autosomes, not elsewhere classified applies to 9 codes
  • trisomies of chromosomes 13, 18, 21 (Q90-Q91)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block Q90-Q99 Chromosomal abnormalities, not elsewhere classified applies to 74 codes
  • mitochondrial metabolic disorders (E88.4-)
From Chapter 17 (Q00-QA1) Congenital malformations, deformations and chromosomal abnormalities applies to 900 codes
  • inborn errors of metabolism (E70-E88)

Notes

General instructions on how these codes are used.

From Chapter 17 (Q00-QA1) Congenital malformations, deformations and chromosomal abnormalities applies to 900 codes
  • Codes from this chapter are not for use on maternal records

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name Q92.1, its category, or a range that includes it.

Excludes1 3

These codes carry an Excludes1 note naming Q92.1: they are not reported together with it, unless the two conditions are unrelated.

  • E25 Adrenogenital disorders
    chromosomal abnormalities (Q90-Q99) names Q90-Q99, which includes this code
  • Block Q50-Q56 Congenital malformations of genital organs
    syndromes associated with anomalies in the number and form of chromosomes (Q90-Q99) names Q90-Q99, which includes this code
  • Z15 Genetic susceptibility to disease
    chromosomal anomalies (Q90-Q99) names Q90-Q99, which includes this code

Code First 1

These codes say to code first a condition named in the note, and Q92.1 is one of the conditions named.

  • D84.81 Immunodeficiency due to conditions classified elsewhere
    chromosomal abnormalities (Q90-Q99) names Q90-Q99, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MAL009
Chromosomal abnormalities
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Genetic Disorders

Genetic disorders are health conditions caused by changes (also called mutations or variants) in your genes. Genes are parts of DNA found in your cells that carry instructions for how your body grows, develops, and functions. Many genes tell your body how to make proteins, which are needed for your body to work properly.

The full article covers:

  • What are genetic disorders?
  • What causes genetic disorders?
  • What are the types of genetic disorders?
  • What are the different ways a genetic disorder can be inherited?
  • How are genetic disorders diagnosed?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert Q92.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
758.5 Autosomal anomalies NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About Q92.1Overview

What is the ICD-10 code for whole chromosome trisomy, mosaicism (mitotic nondisjunction)?

The ICD-10-CM code for whole chromosome trisomy, mosaicism (mitotic nondisjunction) is Q92.1 (sometimes written as Q921). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is Q92.1 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report whole chromosome trisomy, mosaicism (mitotic nondisjunction) on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does Q92.1 group to?

When whole chromosome trisomy, mosaicism (mitotic nondisjunction) is the principal diagnosis on an inpatient stay, it groups to MS-DRG 951 (other Factors Influencing Health Status), which carries a relative weight of 0.5574. Higher weights mean higher Medicare reimbursement.

Is Q92.1 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for whole chromosome trisomy, mosaicism (mitotic nondisjunction) on inpatient claims. The code appears in the Chromosomal abnormalities, not elsewhere classified (Q90-Q99) range of the CMS exempt list.

What is the ICD-9 equivalent of Q92.1?

Under the General Equivalence Mappings, whole chromosome trisomy, mosaicism (mitotic nondisjunction) converts to ICD-9-CM 758.5 (autosomal anomalies NEC). The mapping is approximate, so confirm the match fits the documentation.

Does Q92.1 risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage: Q92.1 maps to no category in the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 148 (Mild or Unspecified Intellectual Disability/Developmental Disorder).