XSense®, Fragile X with Reflex and Chromosome Analysis, Blood
Also known as: FRAX, Fragile X Syndrome (FXS), Fra(X), Martin-Bell Syndrome, Fragile X with Reflex
Use
This test is appropriate as part of the genetic evaluation for individuals with intellectual disability and/or autism of non‐specific etiology. It is also suitable for those with a known family history of fragile X syndrome or other FMR1‑related disorders, in which case a simpler “Fragile X With Reflex” test (without chromosome analysis) may be more appropriate. The test provides both fragile X FMR1 repeat analysis (with reflex methylation PCR if CGG repeats ≥85) and chromosome analysis (karyotype) to detect chromosomal abnormalities such as trisomies, sex chromosome abnormalities, translocations, inversions, marker chromosomes, and mosaicism above ~14 %.
Special Instructions
Not provided.
Limitations
Chromosome analysis cannot detect deletions or duplications smaller than its resolution threshold, single‑gene disorders (e.g., cystic fibrosis, Marfan syndrome, neurofibromatosis), or mosaicism below approximately 14 % (95 % confidence limit).
New York Approved
Methodology
PCR-based (PCR)
Biomarkers
Result Turnaround Time
Not provided.
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
5 mL
Minimum Volume
1 mL (0.5 mL for NICU/Neonates)
Container
sodium heparin (green‑top) tube
Other tests from different labs that may be relevant