Clinical and genetic analysis of ATP13A2 in hereditary spastic paraplegia expands the phenotype

Abstract

Background: Hereditary spastic paraplegias (HSP) are neurodegenerative disorders characterized by lower limb spasticity and weakness, with or without additional symptoms. Mutations in ATP13A2, known to cause Kufor–Rakeb syndrome (KRS), have been recently implicated in HSP. Methods: Whole-exome sequencing was done in a Canada-wide HSP cohort. Results: Three additional patients with homozygous ATP13A2 mutations were identified, representing 0.7% of all HSP families. Spastic paraplegia was the predominant feature, all patients suffered from psychiatric symptoms, and one patient had developed seizures. Of the identified mutations, c.2126G>C;(p.[Arg709Thr]) is novel, c.2158G>T;(p.[Gly720Trp]) has not been reported in ATP13A2-related diseases, and c.2473_2474insAAdelC;p.[Leu825Asnfs*32]) has been previously reported in KRS but not in HSP. Structural analysis of the mutations suggested a disruptive effect, and enrichment analysis suggested the potential involvement of specific pathways. Conclusion: Our study suggests that in HSP patients with psychiatric symptoms, ATP13A2 mutations should be suspected, especially if they also have extrapyramidal symptoms.