Biotinidase deficiency: clinical and MRI findings consistent with myelopathy.

Spastic paraparesis has been described in children with biotinidase deficiency and onset in later childhood and early adolescence. A 3-year-old male with biotinidase deficiency presented with rash, ataxia, and paraparesis and magnetic resonance imaging findings of myelopathy. Improvement occurred after treatment with biotin. Myelopathy should be added to the features that may be found on clinical examination and neuroimaging of children with biotinidase deficiency, regardless of age of presentation.