What is a premutation?

Based on the Quest field, a premutation is 55 to 200 CGG repeats. Most people with a premutation are intellectually typical, but it can carry health and reproductive implications. A genetic counselor can explain.

Does this test diagnose Fragile X syndrome?

No. A full mutation result is associated with Fragile X syndrome, but interpretation and any diagnosis belong with a clinician.

What does "with reflex" mean?

If the first result needs more analysis, the lab can run an additional test on the same sample.

Genetic and Carrier Screening

XSense Fragile X Carrier Screen with Reflex

A blood test that measures CGG repeat length in the FMR1 gene to assess Fragile X carrier and premutation status.