This approach aimed to (1) investigate the phenotypes in terms of onset region, propagation pattern and the degree of upper and lower motor neuron dysfunction, (2) to determine the ALS progression rate, and (3) to measure serum NfL in genetic ALS associated with C9orf72, SOD1, TARDBP and FUS mutations. This evidence concerns the gene C9orf72 and amyotrophic lateral sclerosis.