TARDBP and amyotrophic lateral sclerosis: Mitochondria are a known target of Tdp-43 function [26, 27, 56–60] and are also defective in iPS-cell derived motoneurons harboring ALS mutations [61] and ALS mouse models [62], indicating that defects in energy production upon loss of Tdp-43 might contribute to the axonal growth defect in cultured motoneurons.