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v1.0.0
ICD-10 Guide
DiagnosesRett Syndrome

Rett Syndrome

ICD-10 Coding for Rett Syndrome(F84.2)

PRIMARY SPECIALTYNeurology
COMPLEXITYHigh
LAST UPDATED09/15/2025
Sam Tuffun, PT, DPT
Physical Therapist | Medical Coding & Billing Contributor

Diagnosis Overview

What is Rett Syndrome?
Essential facts and insights about Rett Syndrome

Key Clinical Considerations:

  • Loss of purposeful hand skills
  • Developmental regression after normal early development
  • Repetitive hand movements (e.g., hand-wringing)
  • Gait abnormalities
  • Seizures

Clinical Information

Clinical Criteria & Documentation Requirements

  • Patient history including developmental milestones
  • Neurological examination findings
  • Genetic testing results (e.g., MECP2 mutation)
  • Family history of similar conditions

Coding Guidelines

Usage Guidelines & Examples

  • Use F84.2 for Rett syndrome; avoid using codes for other autism spectrum disorders.
  • Common errors include misclassifying Rett syndrome as a general developmental disorder.

Code Exclusions

Important Exclusions

  • Autism spectrum disorder (F84.0)
  • Other pervasive developmental disorders (F84.1, F84.3-F84.9)

Related ICD-10 Codes

Primary Codes
F84.2
Rett syndrome
Ancillary Codes
G31.8
Differential Codes
F84.0

Related CPT Codes

CPT codes will be available in a future update.

Specialty Focus

Primary Specialty

Neurology

Specialty Applications

  • Pediatric populations
  • Neurology clinics, genetic counseling settings

Coding Complexity

High Complexity

This diagnosis requires careful attention to:

  • Comprehensive clinical documentation
  • Accurate code selection based on clinical criteria
  • Proper exclusion considerations
  • Specialty-specific coding guidelines

Documentation

Documentation Templates

Billing Information

Billing Considerations

  • Ensure proper documentation for billing
  • Verify code specificity requirements
  • Check for any additional codes needed
  • Review payer-specific guidelines

Common Issues

  • Insufficient clinical documentation
  • Incorrect code selection
  • Missing supporting diagnoses
  • Timing and frequency documentation

Frequently Asked Questions

What are the documentation requirements?

Document developmental history, neurological findings, and genetic testing.

What are the billing considerations?

Ensure accurate coding to reflect the severity and associated conditions.