MOK and amyotrophic lateral sclerosis: However, paired-recordings of the CaP-fast-twitch muscle fiber at 6dpf revealed that mok m632−/− NMJs have variable amplitudes and a higher rate of response failure to action potentials, when stimulated at 10, 20 and 100 Hz, similar to what has been described for the FUS loss-of-function ALS model [78].