Main Entry: fragile X syndrome

Pronunciation: \-ˈeks-\

Function: noun

: an X-linked inherited disorder that is caused by repeats of a trinucleotide sequence on the X chromosome which are abnormal in number and degree of methylation, that is characterized by moderate to severe mental retardation, by large ears, chin, and forehead, and by enlarged testes in males, and that often has limited or no effect in heterozygous females—called also fragile X