IGF2R and central precocious puberty: This study showed that single SNPs of the genes in the IGF-1 axis (IGF-1(6093), IGF-1(1770), IGF1R, IGF-2(3123), IGF-2(3580), IGF2R, IGFBP-3(− 202)) did not appear to exert a significant role in the risk for development of CPP.