Regarding the accelerated turnover of N999Vfs*40 KIF5A, this is in line with its lower levels compared to WT KIF5A in iPSC-derived motor neurons harbouring ALS-KIF5A mutations [16, 39] and in ALS-KIF5A animal models [27, 40]. This evidence concerns the gene KIF5A and amyotrophic lateral sclerosis.