Impaired hearing in X-linked hypophosphataemic (vitamin-D-resistant) osteomalacia

We assessed the hearing of 25 patients with X-linked hypophosphataemic osteomalacia. Twelve patients had subjective hearing loss and 2 had had episodic tinnitus, deafness, and vertigo similar to that in Ménière's disease. On pure-tone audiometry, 19 patients were shown to have sensorineural hearing loss, 3 of whom had evidence of an added conductive element. Tests were done to delineate sensory (cochlear) from neural deafness. Analysis of the stapedius reflex threshold, percentage speech discrimination score, tone decay, and loudness recruitment showed a disturbance of cochlear function. The possible mechanisms responsible for this dysfunction are discussed in the light of pathologic characteristics of familial hypophosphataemia and its extraosseous manifestations. Sensorineural hearing loss, a previously unrecognised complication of familial hypophosphataemic osteomalacia, occurs frequently.