A recent study of ALS-FTD brains, using a qPCR assay that did not distinguish if changes in L1 copy number is due to successful retrotransposition or any other mechanism raising the number of L1 copies in gDNA preparations, showed an increase in the L1 copy numbers in TDP-43 negative nuclei [41]. Here, TARDBP is linked to amyotrophic lateral sclerosis.