Fragile X syndrome
Diagnosis and Testing
How do I get tested for fragile X syndrome?
Your doctor or genetic counselor can test a person for fragile X syndrome by using their blood to look at their DNA (their genetic blueprint) and test the specific gene that causes fragile X syndrome when it is mutated: the FMR1 gene. There are many different laboratories that offer FMR1 gene testing either as a single gene test or tested alongside other genes. A full list of the laboratories currently offering testing for fragile X syndrome can be found by visiting GeneTests and entering "fragile X syndrome" into the search box. The "gold standard" for fragile X syndrome testing has been polymerase chain reaction (PCR) testing to determine the number of CGG repeats and Southern blot analysis, which is another method used to detect the number of repeats that can also determine whether the gene is methylated (turned off) or not. This type of testing must be ordered by a physician or genetic counselor who can interpret the results for the patient and their family. If the FMR1 gene is the only gene that is tested, the results usually take 1-3 weeks (depending on the laboratory). If other genes are tested in addition to FMR1, then the results could take several weeks longer to come back. The price of genetic testing is ever-changing, and depends on several factors including deductible status, copays, insurance guidelines, financial assistance (if applicable), and current pricing. More recently, technology has brought the cost of genetic testing down dramatically. A physician or genetic counselor can help advise patients and their families as to what the cost of genetic testing would be to them and counsel them on their options and assistance programs (if needed).
To learn more about testing and find a clinic specializing in fragile X syndrome near you, please visit https://fragilex.org/treatment-intervention/fragile-x-clinics/. To find a genetic counselor, please visit www.nsgc.org and click the "Find a Genetic Counselor" link to locate a provider in your area.