Novel imaging findings in two cases of biotinidase deficiency-a treatable metabolic disorder.

Biotinidase deficiency is one of the few treatable inborn errors of metabolism. We describe unique MRI features in two patients with biotinidase deficiency. Brain MRI in case one demonstrated symmetrical diffusion restriction in bilateral hippocampi, parahippocampal gyri, central tegmental tracts, and cerebellar white matter besides other structures that have been reported previously. The second patient was noted to have bilateral symmetrical T2 hyperintensities involving the anterior, lateral and posterior columns of the entire spinal cord on MRI. Knowledge of the varied MRI features of biotinidase deficiency will aid the prompt diagnosis and treatment of a potentially disabling illness, especially in countries where newborn screening is not routinely performed.