The problem of a rare enzyme disorder being mistakenly diagnosed as neuromyelitis optica spectrum disorder (NMOSD) is highlighted in a new case report involving a child.
“Biotinidase deficiency is a rare, autosomal recessive, metabolic disorder associated with mutations in the BTD gene,” the authors, Jonathan Santoro, MD, and Kelli Paulsen, RN, Children’s Hospital Los Angeles, Los Angeles, California, explain.
“Clinical features are heterogeneous, although optic neuropathy and myelitis have been reported in children. These clinical features can mimic NMOSD,” they add.
The case is outlined in a research letter published online on October 5 in JAMA Neurology.
The authors describe a 13-year-old girl who presented with symptoms of NMOSD ― simultaneous paraparesis and bilateral vision loss. Imaging showed bilateral signal prolongation in the optic nerves. She was treated with intravenous methylprednisolone for NMOSD, but her symptoms worsened.
Repeat imaging at 1 year showed resolution of signal in