First described by McCance [2] and Prader [3], TIO has been associated with increased production of the phosphaturic hormone Fibroblast Growth Factor 23 (FGF23), usually by mesenchymal tumors of soft tissue or bone known as “Phosphaturic Mesenchymal Tumors” (PMTs) [4]. The gene discussed is FGF23; the disease is mesenchymal cell neoplasm.