[2 cases of oto-spondylo-megaephyseal dysplasia]

Spondylo-epiphyseal dysplasia (SED) is a heterogeneous clinical condition covering many skeletal anomalies, particularly of the spinal column and proximal epiphysis of the long bone. It can be associated with several forms of craniofacial malformations, often with ocular pathologies and only rarely with deafness (recently described as Otospondylo-megaepiphyseal dysplasia "OSMED"). When present, hearing loss is mainly neurosensorial and this may be explained by the presence of type II collagen in the inner ear; in fact, the synthesis of this collagen is altered in "OSMED". On the other hand, antibodies vs. type II collagen have been found in patients with pathologies of both articulation and of the inner ear, including sudden hearing loss. The latter pathologies present such antibodies and provide a good prognostic index, even for immunosuppressive therapy. The present work describes two cases of SED with neurosensorial hearing loss, most likely "OSMED", diagnosed in two female patients (mother and daughter). Then there is a discussion of the clinical, anatomopathological and radiological elements that prove useful in evaluating the specific pathology, emphasizing the problems regarding genetics and differential diagnosis between this and other similar cases described in the literature since 1969. Finally, two hypotheses are advanced as to the pathogenesis of the neurosensorial hearing loss, both supported by case history, clinical and instrumental findings from these two patients.