Hereditary spastic paraplegia is a clinically and genetically heterogeneous disorder characterized by progressive spasticity of the lower limbs. Seven loci for autosomal dominant pure hereditary spastic paraplegia (ADPHSP) have already been mapped on chromosomes 14q, 2p, 15q, 8p, 12q, 19q, and 2q. We report on an Italian family affected by ADPHSP for which we excluded linkage with the known loci and performed a genome-wide search. Linkage analysis and haplotype construction permitted the identification of a novel ADPHSP locus on the long arm of chromosome 9, designated SPG19. The phenotype was characterized by late onset (range, 36-55 years) and mild disability, with only 1 patient bound to a wheelchair after 31 years of disease. Urinary disturbances (urgency and/or incontinence) were always present, even in young patients with a short disease history.