Distribution of FMR1 and FMR2 Repeats in Argentinean Patients with Primary Ovarian Insufficiency

Abstract

The premutation state of <i>FMR1</i> (Fragile X Mental Retardation 1) has been associated with primary ovarian insufficiency (POI), and is the most common known genetic cause for 46,XX patients. Nevertheless, very few studies have analyzed its frequency in Latin American populations. Additionally, a relationship between alleles carrying a cryptic microdeletion in the 5'UTR of <i>FMR2</i> and the onset of POI has only been studied in one population. Our aim was to analyze the incidence of <i>FMR1</i> premutations and putative microdeletions in exon 1 of <i>FMR2</i> in a cohort of Argentinean women with POI. We studied 133 patients and 84 controls. Fluorescent PCR was performed, and the <i>FMR2</i> exon 1 was further sequenced in samples presenting less than 11 repeats. We found the frequency of <i>FMR1</i> premutations to be 6.7% and 2.9% for familial and sporadic patients, respectively. Among controls, 1/84 women presented a premutation. In addition, although we did not find microdeletions in <i>FMR2</i>, we observed a change (T >C) adjacent to the repeats in two sisters with POI. Given the repetitive nature of the sequence involved, we could not ascertain whether this represents a single nucleotide polymorphism (SNP) or a deletion. Therefore, a relationship between <i>FMR2</i> and POI could not be established for our population.