We studied the effects of a single nucleotide polymorphism (SNP) (rs8111699) in STK11 on endocrine-metabolic and body composition indexes before and after 1 year of metformin in 85 hyperinsulinemic girls with androgen excess, representing a continuum from prepuberal girls with a combined history of low birth weight and precocious pubarche over to postmenarchial girls with hyperinsulinemic ovarian hyperandrogenism.