Abstract
A patient with a SUNCT-like syndrome caused by severe basilar impression in association with osteogenesis imperfecta is described. Initially symptoms of both the first and second branch of the trigeminal nerve were prominent, on which carbamazepine had only a temporary and mild effect. Progressive symptoms with prominent ipsilateral autonomic features, unexplained triggering by photostimulation, and increasing duration of pain attacks occurred with relentless progressive basilar impression associated with pontomedullary compression. Pathophysiologically a dysfunction in ephaptic transmission is hypothesised.