We conclude that UBQLN-2 mutations related to ALS/FTLD are extremely rare in French FTLD and FTLD-ALS patients and should not be analyzed systematically.
Regardless, the recent finding that additional RNA-binding proteins may also cause ALS, and the observation that TDP-43 aggregation remains a core feature in all of the recently identified genetic forms of ALS (C9ORF72, VCP, UBQLN2, and PFN1), underscores the central role of TDP-43 and RNA metabolism in ALS and FTLD.