Mitochondria control cellular metabolism, serve as hubs for signaling and organelle communication, and are important for the health and survival of cells. encodes a cytoplasmic lipid transfer protein that regulates mitochondrial morphology, mitochondria and endoplasmic reticulum (ER) contact, quality control of mitochondria. mutations have been reported in patients displaying ataxic and spastic gait disorders with variable age of onset. Here we used CRISPR/Cas9 gene editing to create related-spinocerebellar ataxia-4 (SCAR4) missense mutations and C-terminal deletion in 's orthologue in . Consistent with SCAR4 patient movement disorders and mitochondrial dysfunction, mutant worms exhibit locomotion defects and abnormal mitochondrial morphology. Importantly, animals with a deletion or a N3017I missense mutation exhibited an increase in mitochondrial unfolded protein response (UPR ). The cellular and behavioral changes caused by mutations in advance the development of animal models that are needed to study SCAR4 pathogenesis.