Fragile X syndrome is the leading cause of inherited mental retardation, affecting approximately 1 in 4,000 males and 1 in 8,000 females. Women may decide to have testing to find out if they are carriers, and therefore are at risk of having a child with Fragile X syndrome. The carrier frequency in women is approximately 1 in 260.
Carrier testing may be done before or during pregnancy. If a woman is found to be a carrier, prenatal diagnosis by amniocentesis is available. Additionally, indications for fragile X testing include: Individuals with undiagnosed mental retardation, developmental delay or autism; carrier testing for women with infertility problems associated with elevated follicle stimulating hormone (FSH) levels; premature ovarian insufficiency (POI) or unexplained early menopause; and men and women with late onset intention tremor and cerebellar ataxia of unknown origin. Genzyme Genetics fragile X testing includes both PCR and Southern blot analysis to provide the most accurate results.
CPT Codes:
83891(1), 83892(2), 83894(1), 83896(1), 83897(1), 83898(1), 83912(1), 83909(2)
Specimen Requirements:
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Blood:
- ACD-A (yellow-top) or EDTA (lavender-top) tube.
- Adult: 20 ml whole blood.
- Child: 5-7 ml whole blood.
- Turnaround Time:
8-12 days
- Prenatal:
Please Note: Call a laboratory genetic coordinator prior to obtaining any specimens. Prenatal testing is recommended only for women who are carriers with identified mutations. In some circumstances, specimens from other family members may be required.
All prenatal specimens (including cord blood) must be accompanied by a maternal blood specimen for analysis of possible maternal cell contamination.
If amniotic fluid is sent for chromosome analysis, no additional specimen is required. Otherwise, send two T-25 flasks of confluent cells, while maintaining a back-up culture at your facility.
Client Services:
Reproductive/Genetics
800-848-4436
Specimen Services/Pickup:
877-246-1226