Prevalence of cytogenetic abnormalities and FMR1 gene premutation in a Portuguese population with premature ovarian insufficiency

Abstract

Introduction: Chromosome abnormalities contribute to about 10% of cases of premature ovarian insufficiency. Most are associated with X chromosome. Fragile mental retardation 1 (FMR1) gene premutation has an estimated prevalence of 1% - 7% in sporadic cases and up to 13% in familial cases. Our aim was to describe the clinical characteristics, cytogenetic and FMR1 testing of a Portuguese population with premature ovarian insufficiency.Material and Methods: Women diagnosed with premature ovarian insufficiency in a Portuguese tertiary centre were retrospectivelyanalysed. Data were retrieved from electronic medical records including clinical characteristics, cytogenetic and FMR1 testing. The main outcome measures were the prevalence of chromosome abnormalities and FMR1 premutation in a Portuguese population with premature ovarian insufficiency.Results: Ninety-four patients were included, with a median age at menopause of 36 years. The prevalence of chromosome abnormalities was 16.5% (14/85) and most were X chromosome related (78.6%). The prevalence of FMR1 premutation was 6.7% (6/90). The prevalence of karyotypic abnormalities or FMR1 premutation did not differ significantly between familial and sporadic cases. Neither chromosome abnormalities nor FMR1 premutation influenced age at menopause or follicle stimulating hormone levels at diagnosis in premature ovarian insufficiency patients.Discussion: This is the first study describing the clinical characteristics and both cytogenetic and FMR1 testing in a Portuguese population with premature ovarian insufficiency. The rate of chromosome abnormalities in our sample was higher than in other populations, while the prevalence of FMR1 premutation was similar to previous reports.Conclusion: Our results underline the importance of genetic screening in premature ovarian insufficiency patients in both etiological study and genetic counselling.