Whole-genome sequencing of two probands with hereditary spastic paraplegia reveals novel splice-donor region variant and known pathogenic variant in SPG11

Hereditary spastic paraplegias (HSPs) are a group of heterogeneous neurodegenerative disorders, which are often presented with overlapping phenotypes such as progressive paraparesis and spasticity. To assist the diagnosis of HSP subtypes, next-generation sequencing is often used to provide supporting evidence. In this study, we report the case of two probands from the same family with HSP symptoms, including bilateral lower limb weakness, unsteady gait, cognitive decline, dysarthria, and slurring of speech since the age of 14. Subsequent whole-genome sequencing revealed that the patients are compound heterozygous for variants in the SPG11 gene, including the paternally inherited c.6856C>T (p.Arg2286*) variant and the novel maternally inherited c.2316+5G>A splice-donor region variant. Variants in SPG11 are the common cause of autosomal recessive spastic paraplegia type 11. According to the ClinVar database, there are already 101 reported pathogenic variants in SPG11 that are associated with HSPs. To our knowledge, this is the first report of SPG11 variants in our local population. The novel splice variant identified in this study enriches the catalog of SPG11 variants, potentially leading to better genetic diagnosis of HSPs.