Hereditary spastic paraplegias are a heterogeneous group of chronic central motor system disorders, characterised by progressive lower limb spasticity. Hereditary spastic paraplegia is clinically classified into pure and complicated forms, by the absence or presence of additional neurological or extra-neurological features. Hereditary spastic paraplegias follow all modes of inheritance and the pure-form autosomal dominant type is the one most commonly reported. Spastic paraplegia 4, autosomal dominant (SPG4, MIM#182601) and spastic paraplegia 3, autosomal dominant (SPG3A, MIM#182600), account for most autosomal dominant hereditary spastic paraplegias. Using DNA mutation analysis, the authors identified an SPG3A missense mutation (p.R239C) in a Chinese family where three members have early-onset pure spastic paraplegia. To our knowledge, this is the first report of a gene mutation in hereditary spastic paraplegias in our locality. DNA-based diagnosis plays a key role in the early diagnosis of familial hereditary spastic paraplegias.