Late Onset Biotinidase Deficiency Misdiagnosed As Neuromyelitis Optica: A Case Report And Review Of Diagnostic Challenges

A 33-year-old male initially misdiagnosed with neuromyelitis optica was found to have late onset biotinidase deficiency, a condition that can mimic neuromyelitis optica and multiple sclerosis. His symptoms included progressive spastic diplegia, bilateral optic atrophy, and peripheral neuropathy. Serum biotinidase testing revealed a marked deficiency, leading to a revised diagnosis. Treatment with 10 mg of biotin daily is underway, with potential for reversing ophthalmologic findings and some myelopathy. The case highlights the importance of considering biotinidase deficiency in similar clinical presentations, as testing is quick and inexpensive, and can significantly alter management. Further research is needed to understand the incidence of this deficiency in patients with neuromyelitis optica and multiple sclerosis diagnoses.