This single-center, prospective, observational, cross-sectional mechanistic pilot study will evaluate whether polycystic ovary syndrome (PCOS) contributes to hepatic steatosis in adolescent girls independently of adiposity. A total of 150 girls aged 10-18 years will be enrolled into three groups of 50: girls with PCOS and obesity, age- and body mass index-matched girls with obesity but without PCOS, and healthy normal-weight girls. Each participant will undergo a single evaluation comprising anthropometry, clinical and biochemical phenotyping, transient elastography with controlled attenuation parameter and two-dimensional shear wave elastography, and a single venous blood sample.
An extended biomarker panel will be measured by enzyme-linked immunosorbent assay (Fetuin-A, fibroblast growth factor 21, adiponectin, visfatin, cytokeratin-18 M30 and M65, soluble CD163, growth differentiation factor 15, 11-ketotestosterone, and 11beta-hydroxyandrostenedione), together with liquid chromatography-tandem mass spectrometry measurement of testosterone and sex hormone-binding globulin, and genotyping of PNPLA3 rs738409 and HSD17B13 rs72613567. The primary objective is to compare hepatic steatosis and the hepatokine/adipokine profile between the PCOS with obesity group and the adiposity-matched obesity control group, adjusting for body mass index z-score, insulin resistance, and free androgen index. No therapeutic intervention is assigned by the study protocol.