Hypochondroplasia with Foramen Magnum Stenosis: a Case Report

Hypochondroplasia was first reported in the English literature by Beals (1969). The features are similar to those of achondroplasia but are less severe and are usually reported not to involve the skull. The foramen magnum and whole spinal canal are reduced in diameter in achondroplasia, but less so in hypochondroplasia. In this study, we present an unique case of a seven month old child with hypochondroplasia with symptomatic foramen magnum stenosis which required surgical decompression. This 7-month-old child with hypochondroplasia presented with hypotonia and severe respiratory disabilities, including apneic episodes requiring continuous positive airway pressure. Magnetic resonance imaging revealed marked foramen magnum stenosis. Foramen magnum decompression was performed. Postoperatively, steady motor improvement has been observed and the patient no longer requires ventilatory support. To the our knowledge, this is the first report of hypochondroplasia and symptomatic foramen magnum stenosis. In this case we wish to emphasize the necessity of the radiological imaging of foramen magnum and spinal cord for the patient who has respiratory distress and hypotonia with skeletal dysplasia.