Fragile X Syndrome Testing
Fragile X syndrome is the most common form of inherited intellectual disability. Fragile X syndrome occurs among all ethnic backgrounds and racial groups. Approximately 1 in 260 women in the general population are carriers of fragile X syndrome. Additionally, women of all ages can have a child affected with fragile X syndrome, regardless of whether they have had previous healthy children.
- a family history of fragile X syndrome
- a family history of unexplained mental retardation, developmental delay or autism
- infertility problems associated with elevated follicle stimulating hormone (FSH) levels, premature ovarian failure (POF) or unexplained early menopause
Collection Procedure
- Amniotic fluid 15-20 ml. Discard the first 2 ml of fluid to reduce the risk of maternal cell contamination. Aseptically transfer the specimen into sterile plastic conical tubes labeled with patient’s name and date of birth.
- CVS 10-1-20 mg. Aseptically transfer the specimen into sterile plastic conical tubes containing sterile transport medium. Label tube with patient’s name and date of birth.
- Peripheral blood 5-15 ml. Collect whole blood in a lavender top tube (EDTA). Label tube with patient’s name and date of birth.
Specimen Requirements
- Direct testing may be possible an adequate sample is received
- 2-T25 flasks are required for testing and or confirmation
Methodology
Laboratory testing Fragile X Syndrome involves highly sensitive PCR analysis, with reflex to Southern blot for all positive samples to determine the number of CGC repeats present in the Fragile X gene located on chromosome X.
Transport Temperature
Room temperature (DO NOT refrigerate, freeze or centrifuge)
Causes for Rejection
Frozen specimen, clotted or hemolyzed, inappropriate container
Delay in transport >72 hours
Turnaround Time
7-10 days