Hereditary spastic paraplegia(HSP)is a rare neurodegenerative disease due to a length-dependent distal axonopathy of the cortico-spinal tract(Fink,2006).HSP has highly clinical heterogeneity and is classified into pure and complex forms according to the description by Harding(1983).Patients with pure HSP present progressive para-paresis and spasticity of the lower limbs with pyramidal syndromes,including brisk reflexes,spasticity,and so on.It is usually accompa-nied by decreased vibration and sphincter functional disturbance.Complex HSP is characterized by extremity spasticity with additional neurological and extra-neurological symptoms such as neuropathy,seizures,hearing loss,optic atrophy,cerebellar dysfunction,and in-tellectual deficiency(Pensato et al.,2014).HSP also has genetic het-erogeneity.So far,HSPs are divided into many subtypes(SPG 1-83),and more than 60 causative genes have been identified with auto-somal dominant,autosomal recessive,X-linked,and mitochondrial inheritances(Finsterer et al.,2012;de Souza et al.,2017;Farazi Fard et al.,2019;Husain et al.,2020).AD-HSP mainly presents pure type and is usually caused by variants in the SPAST/SPG4 gene(Parodi et al.,2018).AR-HSP is often associated with complex type and is usually caused by variants in the SPG11 and CYP7B1/SPG5 genes(Dong et al.,2018).