Spartin is a protein that in humans is encoded by the SPG20 gene. This gene encodes a protein that contains a MIT (Microtubule Interacting and Trafficking molecule) domain. This protein may be involved in endosomal trafficking, microtubule dynamics, or both functions. Spartin loss has been associated to mitochondrial dysfunction, impaired complex I activity and altered pyruvate metabolism. Frameshift mutations associated with this gene cause autosomal recessive spastic paraplegia 20 (Troyer syndrome).Troyer syndrome (SPG20) is a complicated type of hereditary spastic paraplegias (HSPs). HSP is a category of neurological disorder characterized by spasticity and muscle weakness in the lower limbs.