Through Hardy–Weinberg equilibrium test and haplotype analysis, Wang et al found that IGF1 polymorphism was closely related to the susceptibility to osteonecrosis of the femoral head.[12] Familial osteonecrosis of the femoral head is typically inherited as an autosomal dominant trait,[13] and thus offspring are likely to have the same genetic mutation leading to the disease. The gene discussed is IGF1; the disease is osteonecrosis.