(A) Serum, (B) cerebrospinal fluid (CSF), (C) liver and (D) spinal cord α-tocopherol (α-TOH) concentrations of horses affected with equine neuroaxonal dystrophy (eNAD) and unaffected horses. * P<0.05, ** P<0.01, *** P<0.001, **** P<0.0001 by Mann Whitney test. Data mean ± SEM for n=17–21 eNAD and n=8–12 unaffected (serum, CSF, liver) and n=5 eNAD and n=7 unaffected (spinal cord).