In addition, activating mutations in human FGFR1 cause osteoglophonic dysplasia (OMIM #166250) associated with increased levels of FGF23 and hypophosphatemia [49], which also suggests that activated FGF/FGFR signaling may play a role in regulation of Fgf23 expression. This evidence concerns the gene FGFR1 and osteoglophonic dysplasia.