A, Growth chart for patient 2; height in the upper panel and weight in the lower panel. Age at start of growth hormone is marked by an arrow and the time span of GnRH analog treatment is marked by a double arrow. B, Evaluation of morphology and testicular cell lineage markers in patient 2 (3.5 years of age at time of biopsy). Hematoxylin eosin (HE) staining and immunohistochemical (IHC) staining of OCT4 (marker of gonocytes), MAGE-A4 (marker of spermatogonia), SOX9 (marker of Sertoli cells), CYP11A1 (marker of Leydig cells), and COUP-TFII (marker of peritubular myoid- and Leydig cells). On all IHC images, counterstaining is with Mayer's hematoxylin, scale bar corresponds to 100 μm. GH = growth hormone; GnRH = gonadotropin-releasing hormone.