In FGF23-deficient mice suffering from hyperphosphatemia and hypercalcemia with resulting defective bone mineralization (36), a mixed conductive and sensorineural hearing loss was reported (11), whereas in Hyp mice with FGF23 overexpression and consecutive hypophosphatemia and mineralization impairment, a predominant conductive hearing loss was present (10). This evidence concerns the gene FGF23 and hypophosphatemia.