Aberrant neurofilament accumulations are one of the major pathological features for both SALS and FALS. However no conclusive linkage between mutations in three neurofilament genes and either SALS or FALS patients have been reported, although in-frame insertions or deletions within the normal array of 44-45 lysine serine proline (KSP) repeats region in the tail domain of NF-H have been reported in 1% of SALS cases. In other investigations, dominant point mutations in the NF-L gene have been linked to a mild motor neuron generative discase, Charcot-Marie-Tooth (CMT) disease.