What have we learned form monogenic forms of severe insulin resistance associated with PCOS/HAIRAN?

Whatever the origin of severe insulin resistance (primary insulin receptors defects or lipodystrophies), in vivo hyperinsulinemia has been clearly shown to promote ovarian growth and androgen synthesis independently of gonadotropins. In lipodystrophic syndromes, the endocrine deficiency of adipose tissue has been shown to play important pathophysiological roles in metabolic alterations. In particular leptin is decreased, contributing to the ectopic lipid storage in non-adipose cells, which inhibits insulin signalling (lipotoxicity). Finally, polycystic ovary syndrome (PCOS) features are not always present in insulin resistance syndromes with lipodystrophy. This is in favour of an aggravating, but not a primary role of post-receptor insulin resistance on ovary dysfunctions.