GRN and amyotrophic lateral sclerosis: Pathogenic mutations of the progranulin gene have been found associated with FTD (but not ALS) and result in reduced progranulin in the CSF.157 It is not changed in CSF of ALS compared with healthy controls,158 and there is no correlation between CSF and serum progranulin.159 Progranulin and granulin peptides produced by proteolysis that promotes inflammatory activity are produced by many types of tissue.160 Taken together, including the size of the whole molecule, the usefulness of urinary progranulin as a biomarker for ALS is not clear.