Fragile X Syndrome
Short Description or Definition
Fragile X (FXS) is a neurodevelopmental disorder that is caused by an unstable expansion (CGG repeats) in the FMR1 gene on the X chromosome. FXS is the most common form of inherited intellectual disability (ID). FXS in can result in physical features including prominent ears, elongated face, flat feet, macroorchidism (enlarged testicles in males), connective tissue abnormalities, and epilepsy, among others. Males are generally more severely affected than are females. In addition to ID and various cognitive weaknesses, high rates of autism spectrum disorder (ASD) and attention/deficit hyperactivity disorder (ADHD) have been identified.
Classification of FXS is based upon the size of CGG trinucleotide repeats within the FMR1 gene located on the X chromosome. In the general population, 6–55 repeats are routinely transmitted in a...
- Chromik, L. C., Quintin, E. M., Lepage, J. F., Hustyi, K. M., Lightbody, A. A., & Reiss, A. L. (2015). The influence of hyperactivity, impulsivity, and attention problems on social functioning in adolescents and young adults with fragile X syndrome. Journal of Attention Disorders. https://doi.org/10.1177/1087054715571739. [Epub ahead of print].PubMedPubMedCentralGoogle Scholar
- For more information on FXS, visit the National Fragile X Foundation website at http://www.fragilex.org
- Hagerman, R. J. (2002). Physical and behavioral phenotype. In R. J. Hagerman & P. J. Hagerman (Eds.), Fragile X syndrome: Diagnosis, treatment and research (3rd ed., pp. 136–168). Baltimore: The Johns Hopkins University Press.Google Scholar
- Hagerman, R. J. (2008). Etiology, diagnosis, and development in fragile X syndrome. In J. E. Roberts, R. S. Chapman, & S. F. Warren (Eds.), Speech and language development and intervention in down syndrome and Fragile X syndrome (pp. 27–49). Baltimore: Paul H. Brookes Publishing.Google Scholar
- Quintin, E. M., Jo, B., Hall, S. S., Bruno, J. L., Chromik, L. C., Raman, M. M.,. .. Reiss, A. L. (2015). The cognitive developmental profile associated with fragile X syndrome: A longitudinal investigation of cognitive strengths and weaknesses through childhood and adolescence. Development and Psychopathology 1–13. https://doi.org/10.1017/S0954579415001200 [pii]
- Sherman, S. (2002). Epidemiology. In R. J. Hagerman & P. J. Hagerman (Eds.), Fragile X syndrome: Diagnosis, treatment and research (3rd ed., pp. 136–168). Baltimore: The Johns Hopkins University Press.Google Scholar