RIPK1 and amyotrophic lateral sclerosis: ALS is a heterogeneous disease involving a variety of pathogenic genes such as OPTN, NEK1, and TBK1 and risk factors.5,21,22 Mutant mice with deficiencies in OPTN, NEK1, and TBK1 are sensitized to the activation of RIPK1 kinase and RIPK1-dependent programmed cell death which can be blocked by RIPK1 inhibitor.6–8,23 Clinical trials should be conducted to test the efficacy of primidone in ALS patients, particularly the subtypes caused by loss-of-function mutations of OPTN, NEK1, TBK1, and other ALS risk genes.