Hereditary spastic paraplegia can be classified as uncomplicated (causing paraparesis alone) or complicated (causing other neurological features in addition to paraparesis),1 and since SP can be the earliest manifestation of PSEN1-related Alzheimer’s disease, PSEN1 mutations should be considered in the differential diagnosis of apparent inherited myelopathies.2,3. This evidence concerns the gene PSEN1 and early-onset autosomal dominant Alzheimer disease.