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Atypical presentation of biotinidase deficiency: masquerading neuromyelitis optica spectrum disorder
  1. Farhan Ali,
  2. Khairunnisa Mukhtiar,
  3. Mohammad Raza and
  4. Shahnaz Ibrahim
  1. Women and Child Health, The Aga Khan University, Karachi, Sindh, Pakistan
  1. Correspondence to Dr Khairunnisa Mukhtiar; khairunnisa.mukhtiar{at}


Biotinidase deficiency (BTD) is a treatable, inherited metabolic disorder commonly characterised by alopecia, dermatitis, seizures and developmental delay. It can also manifest as optic neuritis and myelitis; however, these are infrequently described in the literature. We report three cases who presented with quadriplegia and vision loss, initially managed as neuromyelitis optica spectrum disorder (NMOSD), based on neuroimaging findings. Two of them initially responded to immune therapy but relapsed after a few months, while one case showed no clinical improvement with immune therapy. The clinical presentation and neuroimaging findings in all three cases were consistent with NMOSD, leading to a delayed diagnosis of BTD. Antiaquaporin4 and antimyelin oligodendrocyte glycoprotein antibodies were negative in all patients. Urine organic acids reported raised markers of biotinidase or holocarboxylase synthase deficiency. Two of them had a dramatic response to biotin supplementation, showing significant improvement in motor function and vision.

  • Neurology (drugs and medicines)
  • Metabolic disorders
  • Vitamins and supplements

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  • Contributors KM and FA came up with the concept of the manuscript. FA contributed to the original drafting of the text and editing of the clinical images. KM and SI critically revised the manuscript for important intellectual content and interpretation of results. MR contributed to the acquisition of the data and revision of the manuscript. All authors gave their final approval of the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.