LabCorp and its Specialty Testing Group, a fully integrated portfolio of specialty and esoteric testing laboratories.

Fragile X

Fragile X AGG repeats

One fast result for fragile X risk assessment, now enhanced with AGG analysis

What do we mean by one fast result? One lab, one report, one simultaneous and precise result for fragile X syndrome.

AGG analysis in women who have a premutation with 55-90 CGG repeats provides a more accurate risk assessment compared to CGG testing alone.1-3 And with our unique, integrated approach, this combined CGG/AGG fragile X result is available without extending turnaround time, providing you and your patients with one timely and more refined risk estimate.

Dedicated genetic testing for fragile X syndrome

In addition to a comprehensive screening for more than 110 genetic disorders (Inheritest), we also offer single gene screening for certain disorders, such as fragile X syndrome, the most common inherited form of intellectual disability, and a common known cause of autism.4

Fragile X syndrome is found among a variety of ethnic groups,5 and can occur in families with no history of intellectual disability. Approximately one in 260 women5 and one in 800 males6 in the general population is a fragile X carrier. Females who are carriers are at increased risk to have affected children and have an increased risk for fertility problems, including early menopause. Male or female fragile X carriers may develop tremors and balance problems later in life, but male carriers are not at risk to have an affected child.

Choice in testing for fragile X syndrome

At Integrated Genetics, our focus is offering the right test at the right time to the right patient, which is why we offer two types of testing for fragile X: carrier screening and diagnostic.

Carrier screening
Carrier screening for fragile X syndrome is commonly used for individuals both when there is no family history suggestive of the syndrome, and also for unaffected individuals who may have a family history of fragile X syndrome, fragile X-associated disorders (primary ovarian insufficiency, or late-onset ataxia), or unexplained intellectual disabilities, developmental delay, or autism.

Diagnostic testing
We’re able to perform diagnostic tests for fragile X syndrome both during pregnancy (prenatal testing) and after a child is born (pediatric testing).

Prenatal testing is for female carriers of fragile X syndrome who are currently pregnant, or women with primary ovarian insufficiency or failure, premature menopause, or infertility associated with elevated FSH levels before the age of 40 with no known cause. Pediatric diagnostic testing is typically for individuals with unexplained intellectual disabilities, developmental delay, or autism.

Sample requirement and turnaround time

Carrier screening and diagnostic testing for symptomatic individuals requires a blood sample or mouthwash and results are typically ready within 5 to 8 days (6 to 14 for diagnostic tests).

Do you have patients who have not had a test and have questions about costs or coverage? Send them to our estimator.

Do you have patients who have already had a test performed and are wondering when their results will be in? We can help.

Patients with questions about their test results who need schedule an appointment with a counselor can do so online.

References

1. Yrigollen CM, Durbin-Johnson B, Gane L, et al. AGG interruptions within the maternal FMR1 gene reduce the risk of offspring with fragile X syndrome. Genet Med. 2012. 14(8):729–736
2. Nolin SL, Sah S, Glicksman A, et. Al. Fragile X AGG analysis provides new risk predictions for 45-69 repeat alleles. Am J Med Genet Part A 2013. 161A:771-778
3. Nolin SL, Glicksman A, Ersalesi N, et al. Fragile X full mutation expansions are inhibited by one or more AGG interruptions in premutation carriers. Gen Med, 2015 May;17(5):358-64
4. Carrier Screening for Genetic Conditions. ACOG Committee Opinion, Number 691. March 2017
5. Carrier Screening for Fragile X syndrome. ACOG Committee Opinion, Number 469. October 2010
6. Dombrowski, C., et al. Premutation and intermediate-size FMR1 alleles in 10,572 males from the general population: loss of an AGG interruption is a late event in the generation of Fragile X syndrome alleles. Hum Mol Genet 2002; 11(4):371–378