Fragile X syndrome affects approximately 1 in 4,000 males and 1 in 8,000 females. The majority of males with fragile X syndrome have a significant intellectual disability. The spectrum ranges from learning disabilities to severe mental retardation and autism. About one third of the females affected with fragile X syndrome have a significant intellectual disability. Others may have more moderate or mild learning difficulties. To learn more about fragile X syndrome, view or download the Fact Sheet.

Who Should Take It?

• All individuals of child bearing age, regardless of gender
• All individuals with a family history of genetic disorders
• All individuals with partners who are carriers of a genetic disorder
• Couples or individuals considering in vitro fertilization
• Pregnant women

Why Clarity Genetics?

When testing, our laboratory analyzes all of the coding DNA in a gene to determine if any disease-causing pathogenic variants are present. By sequencing all of the coding DNA in a gene, instead of just a portion, we are able to offer the most accurate genetic testing available, regardless of your ethnicity. The majority of laboratories are only sequencing a portion of the gene, leaving room for error with missed pathogenic variants, especially when testing a variety of ethnicities. By sequencing the entire gene, Clarity Genetics testing eliminates the doubt in a negative result and drastically reduces the residual risk, regardless of ethnicity.

Test References:

1. Chen et al. (2010).  An information-rich CGG repeat primed PCR that detects the full range of fragile X expanded alleles and minimizes the need for Southern blot analysis.  J Mol Diagn, 12:589-600.
2. Cornish et al. (2004).  Annotation: Deconstructing the attention deficit in fragile X syndrome: a developmental neuropsychological approach.  J Child Psychol Psychiatry, 45(6):1042-1053.
3. Cronister et al. (2008).  Prevalence and instability of fragile X alleles: implications for offering fragile X prenatal diagnosis.  Obstet Gynecol, 111:596-601.
4. Eichler et al. (1994).  Length of uninterrupted CGG repeats determines instability in the FMR1 gene.  Nat Genet, 8:88-94.
5. Fernandez-Carvajal et al. (2009).  Expansion of an FMR1 grey-zone allele to a full mutation in two generations.  J Mol Diagn, 11:306-1310.
6. Hagerman et al. (2002).  Fragile X syndrome : Diagnosis, treatment, and research; 3rd ed.; Baltimore : Johns Hopkins University Press.
7. Hagerman and Hagerman (2004).  The fragile-X premutation: a maturing perspective. Am J Hum Genet, 74(5):805-16.  Epub 2004 Mar 29. Review. Erratum in: Am J Hum Genet. 2004 Aug;75(2):352.
8. Hagerman (2006).  Lessons from fragile X regarding neurobiology, autism, and neurodegeneration.  J Dev Behav Pediatr, 27(1):63-74.
9. Hantash et al. (2011).  FMR1 premutation carrier frequency in patients undergoing routine population-based carrier screening: insights into the prevalence of fragile X syndrome, fragile X-associated tremor/ataxia syndrome, and fragile X-associated primary ovarian insufficiency in the United States.  Genet Med, 13:39-45.
10. Jacquemont et al. (2007).  Fragile-X syndrome and fragile X-associated tremor/ataxia syndrome: two faces of FMR1.  Lancet Neurol, 6(1):45-55.
11. Koukoui and Chaudhuri (2007).  Neuroanatomical, molecular genetic, and behavioral correlates of fragile X syndrome.  Brain Res Rev, 53(1):27-38.
12. Nolin et al. (2003).  Expansion of the fragile X CGG repeat in females with premutation or intermediate alleles.  J Hum Genet, 2003, 72:454-464.
13. Sherman et al. (2005).  Fragile X syndrome: diagnostic and carrier testing.  Genet Med, 7(8):584-587.
14. Strom et al. (2007).  Molecular testing for Fragile X Syndrome: lessons learned from 119,232 tests performed in a clinical laboratory.  Genet Med, 9:46-51.
15. Terracciano et al. (2005).  Fragile X syndrome.  Am J Med Genet C Semin Med Genet, 15;137(1):32-37.
16. Van Esch (2006).  The Fragile X premutation: new insights and clinical consequences.  Eur J Med Genet, 49(1):1-8.
17. Willemsen et al. (2004).  The fragile X syndrome: from molecular genetics to neurobiology.  Ment Retard Dev Disabil Res Rev, 10(1):60-67.