Pediatric fragile X chromosome

Fragile X syndrome (fragile X syndrome, FXS) is an incompletely apparent X-chromosome-linked dominant inherited disease. It is named for the short arm Xq27.3 of the patient's X chromosome with a fragile break . FXS is a familial mental retardation disease with clinical manifestations of mental retardation, special facial features, giant testis, big ears, speech and behavioral abnormalities. In 1991, scientists first discovered the fragile x syndrome, which is an inherited disease second only to Down's syndrome, and is one of a series of diseases caused by an unusual mutation.