Others report that plasma NfL correlates well with post-mortem neurofibrillary tangle load as well as immunohistochemical measurements of NfL in brain tissue [3] while others have demonstrated that increases in CSF-derived NfL are associated with decreased cerebral glucose hypometabolism [5, 6] as well as decreased cortical thickness [7] in regions that are preferentially affected by AD. The gene discussed is NEFL; the disease is Alzheimer disease.