Ossification of the posterior longitudinal ligament, diffuse, idiopathic skeletal hyperostosis, abnormal retinol and retinol binding protein: a familial observation.

We describe a 52-year-old man who presented with diffuse idiopathic skeletal hyperostosis, ossification of the posterior longitudinal ligament, and abnormal levels of retinol and retinol binding protein (RBP). The molar retinol/retinol binding protein ratio was high, suggesting congenital functional RBP deficiency. His two sons, aged 23 and 27 years, shared the same biological abnormality without clinical symptoms. To our knowledge, this is the first case report of such a familial association.