The antibody used to detect PAR recognizes PAR chains of 20 or more ADP-ribose subunits [52], suggesting that the PAR detected in the ALS spinal cord (see Figs. 2 and 3) is generated from PARP-1 or PARP-2 (collectively known as PARP-1/2). This evidence concerns the gene PARP2 and amyotrophic lateral sclerosis.