MAPPING OF A COMPLICATED FAMILIAL SPASTIC PARAPLEGIA TO LOCUS SPG4 ONCHROMOSOME 2P

Autosomal dominant familial spastic paraplegia (AD-FSP) is a degenerat ive disorder of the central motor system characterised by progressive spasticity of the lower limbs. AD-FSP has been divided into pure and c omplicated forms. Pure AD-FSP is genetically heterogeneous; three loci have been mapped to chromosomes 14q (SPG3), 2p (SPG4), and 15q (SPG6) , whereas no loci responsible for complicated forms have been identifi ed to date. Here we report linkage to the SPG4 locus in a three genera tion family with AD-FSP complicated by dementia and epilepsy. Assuming that both forms of AD-FSP are caused by mutations involving the same FSP gene, analysis of recombination events in this family positions th e SPG4 gene within a 0 cM interval flanked by loci D2S2255 and D2S2347 .