RPL3L and Arrhythmia: However, the fact that mutations in the human RPL3L gene can result in early neonatal lethality, severe cardiomyopathy, and arrhythmia (Ganapathi et al., 2020; Das et al., 2022; Nannapaneni et al., 2022) while Rpl3l−/− mice appear overtly normal as young adults may reflect a lack of compensation by RPL3 in humans or more likely that mutant RPL3L human protein remains fully intact (hence not giving a signal to upregulate RPL3) and is fully incorporated within the 60S ribosome, which causes translational dysfunction.