Most cases of this are identifiable by a constriction at locus Xq27.3 of the namesake structure.  This constriction is caused by methylation due to abnormally frequent CCG repeats in the 5' ["five prime"] UTR of the FMR1 gene.  Clincal features of this disease typically include facial dysplasia and macro-orchidism.  The most common form of inherited mental retardation, this syndrome affects approximately 1 in 2500 children and is twice as likely to afflict males.  FTP, n
Most cases of this are identifiable by a constriction at locus Xq27.3 of the namesake structure.  This constriction is caused by methylation due to abnormally frequent CCG repeats in the 5' ["five prime"] UTR of the FMR1 gene.  Clincal features of this disease typically include facial dysplasia and macro-orchidism.  The most common form of inherited mental retardation, this syndrome affects approximately 1 in 2500 children and is twice as likely to afflict males.  FTP, name this syndrome which derives its name from the penchant of a sex chromosome to break in cultured cells starved for DNA precursors.
Most cases of this are identifiable by a constriction at locus Xq27.3 of the namesake structure.  
{fragile}-{X} syndrome