Ovarian histopathological and ubiquitin-immunophenotypic features in fragile X-associated primary ovarian insufficiency: a study of five cases and selected controls

Sir: The fragile X premutation, an expansion of a CGG triplet repeat in the 5′-untranslated region of the FMR1 gene (55–200 repeats), is one of the most common aetiologies of primary ovarian insufficiency: fragile X-associated primary ovarian insufficiency (FXPOI).1–3 Men who carry the premutation are at increased risk for a late-onset neurodegenerative disorder termed fragile X tremor/ataxia syndrome (FXTAS).4 In premutation carriers, FMR1 is transcribed at increased levels, and the large rCGG tracks may cause disease by acting in a toxic gain of function manner.5–8