Association of infantile neuroaxonal dystrophy and osteopetrosis: a rare autosomal recessive disorder

The association of neuroaxonal dystrophy and osteopetrosis is reported in 2 siblings born to non-consanguineous parents. The 1st child was diagnosed as having infantile osteopetrosis shortly after delivery. A computed tomography scan of the head revealed agenesis of the corpus callosum. She died at the age of 9 months. Post-mortem examination showed pneumonia and bony sclerosis. Neuropathological examination revealed cerebral atrophy, ventricular dilation, absence of the corpus callosum, and a small hippocampus. Neuroaxonal spheroids were found in hippocampus, basal ganglia, pons, medulla, spinal cord, cranial nerves, cerebellum, and peripheral nerves. Ultrastructural examination revealed membranous cytoplasmic bodies and electron-dense granular deposits within the neuroaxonal spheroids as well as the soma of neurons. The 2nd child was delivered at 36 weeks of gestation because of intrauterine fetal distress. The diagnosis of osteopetrosis and partial agenesis of the corpus callosum was made shortly after delivery. The child died at 1 month without an autopsy. There are rare cases reported previously with the association of neuroaxonal dystrophy and osteopetrosis. We review these cases and compare them with ours.