Spatacsin, a protein involved in the growth, and intracellular cargo trafficking of neuronal axons, is produced by the SPG11 gene.25 This gene revealed that codon 247 experiences a frameshift and premature termination in the Italian siblings where ataxia and cognitive decline are the major signs of disease onset at the age of 12 and 15, respectively. This evidence concerns the gene SPG11 and Mental deterioration.