Spastin gene mutation in Japanese with hereditary spastic paraplegia.

Hereditary spastic paraplegia (HSP) is a cluster of genetically heterogeneous disorders that has spastic paraplegia as the central feature. Autosomal dominant HSP (AD-HSP) is also genetically heterogeneous and seven loci have been identified so far on chromosomes 14q (SPG3), 2p (SPG4), 15q (SPG6), 8q (SPG8), 12q (SPG10), 19q (SPG12), and 2q (SPG13). Among them, the SPG4 gene named spastin (GenBank accession No AJ246001) has recently been identified; it is composed of 17 exons and encodes a putative nuclear member of the AAA (ATPases associated with diverse cellular activities) protein family. In the original report, five different mutations were identified in seven families. HSP is a rare disorder in the Japanese population and the prevalence of SPG4 among Japanese AD-HSP patients is unknown. Only one Japanese family has been reported with an insertion mutation in exon 8 of spastin. In order to assess the frequency of spastin mutations in the Japanese, we analysed mutations in probands from 12 Japanese AD-HSP pedigrees.