A Japanese SPG4 Patient with a Confirmed De Novo Mutation of the SPAST Gene.

Spastic paraplegia type 4 (SPG4) is caused by mutations of the SPAST gene and is the most common form of autosomal-dominantly inherited pure hereditary spastic paraplegia (HSP). We herein report a Japanese patient with SPG4 with a confirmed de novo mutation of SPAST. On exome sequencing and Sanger sequencing, we identified the heterozygous missense mutation p.R460L in the SPAST gene. This mutation was absent in the parents, and the paternity and maternity of the parents were both confirmed. The patient showed a pure SPG4 phenotype with an infantile onset. This study may expand the clinical and genetic findings for SPG4.