Novel deletion of SPAST in a Chinese family with hereditary spastic paraplegia

Abstract

Hereditary spastic paraplegia (HSP) belongs to a large, heterogeneous group of progressive neurodegenerative diseases characterised by progressive lower extremity weakness and spasticity, which is caused by developmental failure or degeneration of motor axons in the corticospinal tract. Classical genetic studies have identified at least 46 genetic loci responsible for HSP. A genetic study was conducted on a four-generation Chinese family with autosomal dominant HSP. The SPAST gene was investigated using linkage analysis and direct sequencing. Findings were compared with unaffected family members and 50 normal, unaffected individuals who were matched for geographical ancestry. We identified a novel 14-bp heterozygous deletion that induced a frameshift mutation in exon 15 of SPAST (SPG4). This mutation is predicted to have functional impact and found to cosegregate with the disease phenotype. Our results have expanded the mutation spectrum of the SPAST gene. These findings could help clinicians provide prenatal diagnosis of affected foetuses in families with a known history of such neurodegenerative diseases.