Moms that are Carriers of the Premutation Fragile X Gene

Fragile X syndrome is the most common known cause of mental retardation and developmental disabilities, with an incidence of between 1:2500 and 1:4,000 births. It is a single gene disorder on the X chromosome that occurs in both males and females, but males are typically affected more severely. The disorder can be passed down through generations in a carrier status, with increasing chances of the gene expanding into the full disorder. FXS shuts down the gene responsible for producing FMRP, a protein essential for normal brain function.