Abstract

FOXL2 is a gene encoding a forkhead transcription factor preferentially expressed in the ovary, the eyelids and the pituitary. Its germline mutations are responsible for the blepharophimosis-ptosis-epicanthus inversus syndrome (BPES), which associates eyelid and mild craniofacial defects with primary ovarian insufficiency. Recent studies have shown the involvement of FOXL2 in virtually all stages of ovarian development and function, as well as in granulosa cell-related pathologies. A central role of FOXL2 is the lifetime maintenance of granulosa cell identity through the repression of testis-specific genes. Recently, a highly recurrent somatic FOXL2 mutation leading to the p.C134W subtitution has been linked to the development of Granulosa Cell Tumors in the adult (GCTs), which account for up to 5 % of ovarian malignancies. In this review, we summarize data on FOXL2 modulators, targets, partners and post-translational modifications. Despite the progresses made thus far, a better understanding of the impact of FOXL2 mutations and of the molecular aspects of its function are required to rationalise its implication in various pathophysiological processes.