---
title: "ICD-10-CM F84.2: Rett's syndrome | BillingBrief"
description: "F84.2 covers Rett's syndrome, listed in the F84 group of pervasive developmental disorders. When Rett's syndrome is documented, use F84.2 rather than F84.0…"
canonical: "https://billingbrief.com/icd10/f84.2/"
language: "en"
---

# F84.2 Rett's syndrome

ICD-10-CM · [CMS code reference](#source)

F84.2 covers Rett's syndrome, listed in the F84 group of pervasive developmental disorders. When Rett's syndrome is documented, use F84.2 rather than F84.0, F84.3 or F84.5.

## What to know

-   Excludes1: F84.2 is not coded with autistic disorder (F84.0), other childhood disintegrative disorder (F84.3) or Asperger's syndrome (F84.5). Report the one the provider documents.

## Coding notes

From the ICD-10-CM FY2027 (effective October 1, 2026) tabular list. Notes on a parent code or category apply here too.

### Excludes1

Not coded together with this code. The exception is when the two conditions are unrelated to each other.

-   Asperger's syndrome ([F84.5](https://billingbrief.com/icd10/f84.5/))
-   Autistic disorder ([F84.0](https://billingbrief.com/icd10/f84.0/))
-   Other childhood disintegrative disorder ([F84.3](https://billingbrief.com/icd10/f84.3/))

### Code also

A second code may be needed. Sequencing depends on the encounter.

-   any associated medical condition and intellectual disabilities

## Related codes

-   [`F84.0` Autistic disorder ICD-10-CM](https://billingbrief.com/icd10/f84.0/)
-   [`F84.3` Other childhood disintegrative disorder ICD-10-CM](https://billingbrief.com/icd10/f84.3/)
-   [`F84.5` Asperger's syndrome ICD-10-CM](https://billingbrief.com/icd10/f84.5/)
-   [`F84.8` Other pervasive developmental disorders ICD-10-CM](https://billingbrief.com/icd10/f84.8/)
-   [`F84.9` Pervasive developmental disorder, unspecified ICD-10-CM](https://billingbrief.com/icd10/f84.9/)

## Common questions

### Is F84.2 a billable code?

Yes. F84.2 is a billable ICD-10-CM code in the ICD-10-CM FY2027 (effective October 1, 2026) code set.

## From the source

Official description from [CMS](https://www.cms.gov/medicare/coding-billing/icd-10-codes).
ICD-10-CM FY2027 (effective October 1, 2026).

Code set

ICD-10-CM

Category

F84 Pervasive developmental disorders

Chapter

Mental, behavioral and neurodevelopmental disorders

Billable

Yes

Educational reference only. Not medical, legal, or billing advice. Always check the current official code set and payer policy before you bill. [About BillingBrief and our sources](https://billingbrief.com/about/).