Evaluating plasma 3β,5α,6β-triOH-Gly as a biomarker for NPC in the ataxia cohort indicated that, using the previously determined cut-off of 90 nM, the one individual in the cohort with NPC1 mutations was detected alongside seven other individuals (to be discussed below), so there was a sensitivity of 100% and specificity of 96.2%. This evidence concerns the gene NPC1 and nasopharyngeal carcinoma.