The best cut-off points for differentiating girls with organic CPP and idiopathic CPP with early-stage puberty (Tanner stage 2 and 3) were basal E2 of 38.1 pg/mL (100% sensitivity, 80.4% specificity) and peak LH of 13.6 IU/L(100% sensitivity and 66.4% specificity) ( Table 4 ). This evidence concerns the gene PLOD1 and central precocious puberty.