Ubiquilin2, encoded by UBQLN2, is critical for clearing misfolded proteins and maintaining homeostasis. Pathogenic variants are linked to protein accumulation and stress, but their effects in neural cells remain unclear. We hypothesized that neural cells derived from FTD patient carrying UBQLN2 variants would display impaired proteostasis, mitochondrial dysfunction and oxidative stress. Patient-derived induced pluripotent stem cells were differentiated into neural stem cells (NSC). mRNA and protein levels were quantified by qPCR and Western blot. Reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were measured by flow cytometry with fluorescent probes. Proteasomal activity was assessed by cycloheximide chase of c-Myc degradation. Patient NSC showed elevated Ubiquilin2 levels without mRNA changes, along with reduced Hsp70 and slowed c-Myc degradation, indicating proteostasis defects. NSC also displayed higher ROS, mitochondrial superoxide and hyperpolarized MMP, consistent with mitochondrial dysfunction. In addition, Sirt1 and Sod2 were reduced, reflecting weakened antioxidant defenses. These findings show that UBQLN2 variants impair proteostasis, compromise antioxidant defenses, and induce mitochondrial stress, processes that may drive neurodegeneration. Protein accumulation without mRNA changes highlights defective clearance as a key pathogenic mechanism. This model provides a platform to study UBQLN2-linked disease mechanisms and therapeutic strategies