Spastic Paraplegia, HereditaryParaplegiaParaparesis, SpasticPedigreeAdenosine TriphosphatasesGenes, RecessiveGenes, DominantAdaptor Protein Complex 4Agenesis of Corpus CallosumGenetic HeterogeneityMutationLod ScoreMutation, MissenseATP-Dependent ProteasesMuscle SpasticityPhenotypeAge of OnsetGTP PhosphohydrolasesMicrotubulesAxonsMetalloendopeptidasesDNA Mutational AnalysisCorpus CallosumGenetic LinkageMotor NeuronsHeterozygoteChromosome MappingChromosomes, Human, Pair 2EndosomesMembrane ProteinsSpinal Cord