Neurofilaments (neurofilament light and heavy chain: NfL and NfH, respectively), which are strongly increased in ALS but are also elevated in other neurodegenerative diseases such as atypical Parkinson’s syndromes, are suggested to indicate neuronal damage.37 NfL was significantly elevated in PBC probands compared with controls. The gene discussed is NEFL; the disease is amyotrophic lateral sclerosis.