FMR1 CGG Repeat Analysis

New York




  • Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS)
  • Fragile X Syndrome
  • Premature Ovarian Failure (FMR1-Associated)

Clinical Utility

  • To differentiate fragile X syndrome from other causes of intellectual disability and autism spectrum disorders
  • Preconception/prenatal carrier testing for women with a personal or family history of fragile X syndrome, unexplained intellectual disability, autism spectrum disorders, or POI
  • Carrier testing for at-risk relatives

Lab Method

  • PCR Fragment Analysis

Important Information

The American College of Medical Genetics and Genomics (ACMG) strongly supports exome or genome sequencing as a first-tier test for patients with developmental delay, intellectual disabilities and/or congenital anomalies.


  1. Genetics in Medicine (2021) 23:2029–2037;

Test Code


CPT Codes*

81243x1; +81244x1 if more than 54 repeats

ABN Required


Turnaround Time**

2 weeks

Preferred Specimen

2-5 mL Blood - Lavender Top Tube

Alternative Specimen

Buccal Swabs

*The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

**Turnaround times are estimates and begin once the sample(s) begin processing at the GeneDx lab and could be extended in situations outside GeneDx’s control.