title: Biotinidase deficiency mimicking neuromyelitis optica: Initially exhibiting symptoms in adulthood.
abstract: BACKGROUND
  Children with untreated biotinidase deficiency can experience variable symptoms depending on their age of presentation. Older children and adolescents can exhibit predominant neurological deficits including para- or tetraparesis and vision loss.
  
  
  METHODS
  We report the first case of delayed-onset biotinidase deficiency in a young adult.
  
  
  RESULTS
  A 22-year-old man presented with a disabling extensive myelopathy and bilateral optic neuropathy which mimicked the findings of a (seronegative) neuromyelitis optica. Imaging investigations were characterized by an MRI T2 hyper-intensity involving the spinal cord, the optic nerves, the fornix and the mammillar bodies, together with an increased (18)F-FDG uptake on positron emission tomography. He was ultimately shown to have profound biotinidase deficiency due to a novel missense mutation and was partly improved by oral biotin therapy.
  
  
  CONCLUSIONS
  This individual exemplifies the need to include biotinidase deficiency in the differential diagnosis of patients with extensive myelopathy and/or bilateral optic neuropathy and argues for newborn screening for the disorder.
authors.affiliation: Department of Neurology, Saint-Antoine University Hospital, Paris, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Bottin
authors.affiliation: Department of Neurology, Saint-Antoine University Hospital, Paris, France.
authors.forename: Sabine
authors.initials: S
authors.lastname: Prud'hon
authors.affiliation: Department of Neurology, Saint-Antoine University Hospital, Paris, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Guey
authors.affiliation: Department of Neurology, Saint-Antoine University Hospital, Paris, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Giannesini
authors.affiliation: Department of Research Administration, Henry Ford Hospital, Detroit, USA/Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, USA.
authors.forename: Barry
authors.initials: B
authors.lastname: Wolf
authors.affiliation: Department of Research Administration, Henry Ford Hospital, Detroit, USA/Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, USA.
authors.forename: Kirit
authors.initials: K
authors.lastname: Pindolia
authors.affiliation: Department of Neurology, Saint-Antoine University Hospital, Paris, France/Sorbonne Universités; UPMC Univ Paris 06; UMR S 1127; CNRS UMR 7225; ICM, F-75013, Paris, France bruno.stankoff@sat.aphp.fr.
authors.forename: Bruno
authors.initials: B
authors.lastname: Stankoff
mesh_terms: D000328:Adult; D017668:Age of Onset; D028921:Biotinidase Deficiency / Q000150:complications* / Q000175:diagnosis; D006801:Humans; D008297:Male; D009471:Neuromyelitis Optica / Q000175:diagnosis; D009901:Optic Nerve Diseases / Q000175:diagnosis / Q000209:etiology*; D013118:Spinal Cord Diseases / Q000175:diagnosis / Q000209:etiology*; D055815:Young Adult
keywords: Biotinidase deficiency; myelopathy; neuromyelitis optica; newborn screening; scotoma