FMR1 CGG Repeat Expansion Prenatal Analysis
Use
The FMR1 CGG Repeat Expansion Prenatal Analysis is essential to identify the status of CGG repeats in the FMR1 gene, which is linked to Fragile X syndrome (FXS). FXS is a notable X-linked genetic condition resulting in moderate intellectual disabilities and physiological traits such as characteristic facial features and behavioral challenges. Individuals carrying over 200 CGG repeats are likely to be affected by FXS, whereas those with 55-200 CGG repeats may risk passing the condition to their offspring and may develop associated disorders such as FXTAS and FXPOI. Genetic counseling before testing is crucial for discussing implications, especially for those with family histories of these conditions. Prenatal testing in pregnant patients, particularly with known family connections to FXS or those whose partners are carriers, allows for informed reproductive choices and management.
Special Instructions
Referring centers must consult with laboratory genetic counselors for prenatal cases before submitting samples. A call to 1-800-411-4363 is required for this coordination. This conversation is critical to ensure proper understanding of results and implications, allowing for informed decision-making regarding prenatal testing and potential outcomes. It fosters a collaborative approach to managing genetic risks inherent to fragile X syndrome and its associated conditions.
Limitations
The analysis is highly sensitive for identifying premutation carriers but may not capture all variants leading to FXS. Testing is limited to the FMR1 gene and may miss other related genetic variations affecting the pregnancy outcomes. There is also the potential for instability in repeat sequences, particularly in women who may carry AGG triplets which could affect inheritance patterns. Results may have significant emotional implications; thus, counseling before and post-testing is recommended to support families navigating potential impacts on future generations.
Methodology
PCR-based (PCR)
Biomarkers
Result Turnaround Time
21 days
Related Documents
For more information, please review the documents below
Specimen
Tissue (Fresh)
Volume
Send 2 T-25 flasks
Minimum Volume
N/A
Container
Insulated container
Collection Instructions
Send at about 80% confluency; for confirmation, send samples from a separate primary.
Storage Instructions
Ship at room temperature; do not freeze
Causes for Rejection
Frozen samples are unacceptable.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 48 hours |