TRα1PV/+ mice, which are lacking TRα1, exhibit skeletal hypothyroidism with delayed endochondral ossification and severe postnatal growth retardation.(14) TRα1PV/+ mice also have impaired Igf1r expression and IGF-1 signaling in the growth plate, suggesting that the IGF1R is a physiologic target for thyroid hormone action in the growth plate.(14). The gene discussed is IGF1R; the disease is hypothyroidism.