Our findings are in line with the fact that a DHTKD1 variant detected in three ALS patients of cohort 1 was previously described in infantile-onset SMA, another motor neuron disorder characterized by muscular atrophy and weakness due to LMN degeneration, whereby the variant was heterozygous in late-onset ALS and homozygous in infantile-onset SMA [12]. Here, DHTKD1 is linked to proximal spinal muscular atrophy.