The hereditary spastic paraplegias (HSPs) are a group of clinically and genetically heterogeneous disorders characterized by progressive lower-limb spasticity. In this study, we performed linkage analysis on an autosomal recessive pure HSP family and mapped the disease to chromosome 10q22.1-10q24.1, a locus partially overlapping the existing SPG9 locus. We have either identified a novel locus for pure recessive HSP (SPG27), or we have found the first case of allelic disorders with different mode of inheritance in HSP. If the disorders are indeed allelic, our results have reduced the SPG9 interval by 3Mb with D10S536 and D10S1758 as flanking markers.