RESUMO
The hereditary paraplegias are a heterogeneous group of genetic disorders characterized mainly by spastic paraparesis, which may be found as an isolated "pure form" known as Strümpell-Lorrain syndrome, or associated with a wide group of other manifestations [Harding, 1990; McKusick, 1994]. We studied two unrelated families, one with five members and the other with 11 members (over four generations), affected by a syndrome of late onset spastic paraparesis and dementia. Both pedigrees suggest an autosomal dominant pattern of inheritance. However, this cannot be concluded definitely because male-to-male transmission was not seen. Since this disorder has a late age of onset, we still do not know who will become affected in the second, third, and fourth generations. The association of late onset spastic paraparesis and dementia, without other pathological findings, has not been reported and probably represents a distinct entity.