Nicotinamide Riboside Improves Ataxia Scores and Immunoglobulin Levels in Ataxia Telangiectasia

Background Treatment of animal models with ataxia telangiectasia (A‐T) with nicotinamide riboside (NR) improved their neurological outcome and survival. Objective The aim of this study is to investigate the effects of NR in patients with A‐T. Methods In this open‐label, proof‐of‐concept study, 24 patients with A‐T were treated with NR during four consecutive months. The effects of NR on ataxia, dysarthria, quality of life, and laboratory parameters were analyzed. Results During treatment, ataxia scores improved; mean total Scale for the Assessment and Rating of Ataxia and International Cooperative Ataxia Rating Scale scores decreased to 2.4 and 10.1 points, respectively. After NR withdrawal, ataxia scores worsened. In immunodeficient patients, the mean serum IgG concentration increased substantially until the end of the study period with 0.52 g/L. Untargeted metabolomics analysis revealed increased plasma levels of NR metabolites and purine nucleosides during treatment. Adverse effects did not occur. Conclusions Treatment with NR is tolerated well and associated with improvement in ataxia and serum immunoglobulin concentrations in patients with A‐T. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society