Autosomal dominant familial spastic paraplegia: report of a large New England family.

A large New England family with autosomal dominant familial spastic paraplegia is described. In a pedigree of 173 individuals, 71 affected individuals are identified. Seventeen cases examined by the authors are described with regard to the natural history of FSP in this family. A staging system for following progress and planning interventions is proposed. Three illustrative cases are presented. In this family, FSP is found to have a homogeneous clinical course with nearly complete penetrance. Onset occurs at or before 3 years of age with involvement limited to the lower extremities. After the initial onset, no significant progression was noted. Early aggressive habilitative care may result in more functional ambulation.