To date, the causative genes or gene loci of HSPs, from SPG1 to SPG79, have been reported, and other hereditary diseases including Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS), Chediak-Higashi syndrome, adrenoleukodystrophy, dystonia 4, and others, also exhibit leg spasticity as their one of the symptoms. The gene discussed is L1CAM; the disease is Autosomal recessive spastic ataxia of Charlevoix-Saguenay.