<P> Fragile X syndrome is typically due to an expansion of the CGG triplet repeat within the Fragile X mental retardation 1 ( FMR1 ) gene on the X chromosome . This results in not enough fragile X mental retardation protein ( FMRP ) , which is required for normal development of the connection between neurons . Diagnosis is by genetic testing to determine the number of CGG repeats in the FMRI gene . Normal is between 5 and 40 repeats , fragile X syndrome occurs with more than 200 , and a premutation is said to be present when a middle number of repeats occur . Testing for premutation carriers may allow for genetic counseling . </P>
<P> Fragile X syndrome is typically due to an expansion of the CGG triplet repeat within the Fragile X mental retardation 1 ( FMR1 ) gene on the X chromosome . This results in not enough fragile X mental retardation protein ( FMRP ) , which is required for normal development of the connection between neurons . Diagnosis is by genetic testing to determine the number of CGG repeats in the FMRI gene . Normal is between 5 and 40 repeats , fragile X syndrome occurs with more than 200 , and a premutation is said to be present when a middle number of repeats occur . Testing for premutation carriers may allow for genetic counseling . </P>
how did fragile x syndrome get its name
how did fragile x syndrome get its name
expansion of the CGG triplet repeat within the Fragile X mental retardation 1 ( FMR1 ) gene on the X chromosome
expansion of the CGG triplet repeat within the Fragile X mental retardation 1 ( FMR1 ) gene on the X chromosome