Peyman Hadi - Department of biology, Sanandaj Branch, Islamic Azad University, Kurdistan, Iran

Fragile X syndrome is the most common cause of inherited mental retardation. Patients with fragile X syndrome show variable mental disability, typical long and narrow facial appearance with large ears and prominent fontanelle and frequent macro-orchidism. The fragile site is on the long arm of X chromosome in X q27.3 region. Incidence of syndrome is 1 in 2000 in males and 1 in 2500 in females. This fragile site is visible only with using of special cultural technices. At the molecular level, the fragile X syndrome is associated with an amplification of CGG repeat sequence of the FMR1 gene. The aim of this study was to determine FXS prevalence in moderate Mentally retarded people in iran

Fragile X syndrome, FMR1, karyotype, mental retardation