Evaluation of Adult Biotinidase Activity in Patients with Idiopathic Inflammatory Demyelinating Diseases

Delayed-onset biotinidase deficiency can mimic neuromyelitis optica spectrum disorders. We aimed to evaluate adult serum biotinidase activitiy in central nervous system idiopathic inflammatory demyelinating diseases. This cross-sectional study was conducted in our demyelinating diseases outpatient clinic between January and September 2021. Patients with diagnosis of multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), radiologically isolated syndrome (RIS), or clinically isolated syndrome (CIS) were recruited. Patients’ demographic, clinical, laboratory, and radiological data were noted. Serum biotinidase activitiy were determined by enzymatic analysis. In line with the recommendation of the American College of Medical Genetic guide, the average adult biotidinase activity value was obtained in 100 healthy adults (9.61 nmol/mL/min) for our laboratory and this value was taken as a reference in our study. There were 187 participants (72% were female, mean age: 35.4 ± 9.3 years). In terms of biotinidase activity, there was no significant difference between MS, NMOSD, RIS, CIS (p = 0.249). The patients’ biotinidase activity (mean 8.61) was lower than the reference healthy adult activity (mean 9.61), and 68% (n = 128) of the patients had low biotidinase activity. There were no significant differences between patients with low (n = 128) or normal (n = 59) biotinidase activity for optic neuritis and myelitis (p = 0.408, p = 0.164). We found no correlation between biotinidase activitiy with expanded disability status scale scores and number of magnetic resonance imaging lesions. This study suggested that patients with idiopathic inflammatory demyelinating diseases have lower biotinidase activitiy than healthy people. Determination of biotinidase activitiy and appropriate supplementation of biotine could improve clinical outcomes.