CGG repeat expansion associated with the 5′ UTR region of the FMR1 gene leads to neurodegenerative disorders such as FXS (also called FRAXA), FXTAS, fragile X-associated primary ovarian insufficiency (FXPOI), and fragile X-associated diminished ovarian insufficiency (FXDOR)6,7,39,40. Here, PSMB5 is linked to fragile X syndrome.