A Treatable Cause of Myelopathy: Biotinidase Deficiency Presenting as Acute Flaccid Paralysis.

Biotinidase deficiency (BD) is a rare treatable cause of neurometabolic disorders. It is an autosomal recessive disorder that manifests with cutaneous and neurological manifestations. Spinal cord involvement is uncommon with only a few cases reported in the literature. A 6-year-old female child presented with progressive difficulty in walking since 2 months. At 6 months of age, the child was elsewhere evaluated for global developmental delay and suspected as metabolic disorders and started on megavitamins, following which the child was improved. For the past 2 years, she has stopped medicines. On examination, irritable, alopecia, eczema, hypotonia, and power of two-fifths in all four limbs, and exaggerated deep tendon reflexes. The magnetic resonance imaging (MRI) brain and spine showed T2/fluid-attenuated inversion recovery (FLAIR) hyperintensities in periaqueductal gray matter, dorsal midbrain, pons, medulla, and cervical cord. She was suspected to have BD and confirmed by low enzyme levels and pathogenic variant in BTD . She was started on biotin supplements that resulted clinically dramatic improvement and MRI became normal within 4 weeks. Any child presenting with acute flaccid paralysis with brainstem and spinal cord noncompressive lesions on MRI, rare treatable conditions like BD should be considered in developing countries, like India, where still no universal newborn screening facilities are available. Thieme. All rights reserved.