CRANIOMETAPHYSEAL AND CRANIODIAPHYSEAL DYSPLASIA, HEAD AND NECK MANIFESTATIONS AND MANAGEMENT

Craniometaphyseal and craniodiaphyseal dysplasia are rare genetic diso rders of bane due to modelling errors of long bones and skull bones. T hese syndromes present with multiple ENT symptomatology from an early age. The diagnostic distinction can now be made radiologically by seri al skeletal survey which is important for prognosis. We review the cli nical, radiological, computed tomography (CT) scan, otological, audiol ogical and histopathological findings in two cases with craniodiaphyse al, and two cases with craniometaphyseal dysplasia, and report our exp eriences of medical and surgical treatment to date. In the craniodiaph yseal dysplasia, the hearing abnormality progressed from an initial co nductive to a mixed loss on serial audiometric follow up. Temporal bon e CT scans showed narrowing of the middle ear cavity, internal auditor y meatus, and facial nerve canal at the geniculate ganglion. Benefits from choanal stenosis surgery, craniofacial remodelling and dacrocysto rhinostomy were shortlived. Calcitriol therapy with a low calcium diet did not alter the clinical course of progression in our cases. The un derlying defect, causing net bone formation in these phenotypically si milar syndromes, appears to be different when based on the differing b iochemical responses to calcitriol and bone biopsy findings. Increased numbers of osteoblasts were found in bone biopsies from both cases wi th craniodiaphyseal dysplasia. Early recognition is crucial in these c onditions as therapy directed at the underlying bony defect has the be st chance of success if initiated in infancy (Cole et al., 1988; Fanco ni et al., 1988).