Table 4.

Hurdles on the road of developing novel treatments for ALS and FTD

• Unknown etiology of sporadic cases.

• High degree of heterogeneity at clinical, neuropathological level.

• High degree of genetic heterogeneity both at allele and at locus level.

• Unknown reason(s) for the selective vulnerability of cell types (i.e., specific motor neurons, frontal, and temporal neurons).

• Unknown influence of exogenous factors on the onset and progression of the diseases.

• Unknown influence of endogenous modifier factors on the onset and progression of disease.